LS Swap Seafari 25
 

Guys,

I wasn’t sure if I should put this under my restore thread but I ultimately decided this way might be easier for others searching. My apologies if this bothers you, dear reader.

I’d like to thank and acknowledge all of you guys that have helped me LOTS. Strick, Blue Heron, Terry, Don V, and K Moose. Thank you and thanks to all of you that have encouraged and given input. Especially for the CG estimator! You guys are the best almost as good as our boats.

My seafari 25 was converted from twin I/O’s somewhere in its life to an Outboard. The deck space is just amazing. But the Outboard went DOA due to a flywheel. New Outboards are expensive and even heavier. When you do the math you will get better hp and handling and retain a purity that was the original boat.

So you will lose some deck space no 2 ways about it. I’m consoling myself with plans of a teak swim platform. My plans for my boat is serious offshore fishing for ono (wahoo), ahi (yellowfin tuna), and marlin.

Step 1 you need to locate a LS. I have a LMG 5.3 out of a Silverado 1500. I’ve known my friend for years so I know it’s history. I also got the engine for free.

After you locate your donor vehicle you will need to plan out your build. I HIGHLY recommend a closed cooling system in salt water environments. Also consider what outdrive you will use. I’ve heard of guys using 400hp on alpha drives. I’m finding awesome deals on Bravos. That’s a better option, IMO.

I’m looking for max hp on these but I can’t find one. In 73 these had up to 500+hp through twin mercruisers based on 351W block and as low as 330hp.

My goal is to build a 5.3 as close to 500 as I can on a reasonable budget. There are plenty of how to’s on pulling a Ls, so I won’t be labor that. I do want to suggest pulling the heads and undoing the bell housing bolts that way instead of removing driveshaft and unbolting the tranny. Saved me hours.

https://i.postimg.cc/Y4bJk4C6/A44F24...20D99E99CB.jpg

https://i.postimg.cc/DJg0rKmT/4AFE45...5E6DC98427.jpg

https://i.postimg.cc/hfwjbs4f/34938F...D77CB189D3.jpg

Here’s the oil leak I found. Look you will see the o-ring protruding from fill tube.
https://i.postimg.cc/f3QR1b9s/0C25E7...FADF1D2563.jpg

https://i.postimg.cc/bDr4vzZK/F9539D...95CD188D40.jpg

https://i.postimg.cc/HVjnyRgq/D56304...B96133CAC3.jpg

https://i.postimg.cc/R69qJ0Sd/DB079E...41E747C3BB.jpg

The engine is ready to pull today.

I will be deleting the VVT, Putting a new camshaft in, and a tuner (Holley terminator x?).

I’ll make a parts list and sources as I go. Wish me luck all.

Here’s a beginner list from others. All input appreciated I’m making a plan as I tear down and build the motor. I believe all big hurdles are addressed so far.

I do plan on running direct port injection (injectors) vs a carb setup. This means you will need a map sensor. Many harnesses do not offer a MAP sensor, so be forewarned. I did really consider building a 383 stroker with the mercruiser elbows and risers. I did consider changing out the heads for merc style old 350 heads. The intake will not work and my engine has a TBSS on it and I’m not sure about 350 heads on a LS I know reverse can be done change my mind if you can. I got this engine free and it helps a friend. I believe it will cost less, produce the max power a bravo can handle, and be more reliable over the long run. Ps it has 243 heads on it too. I’d rather have 706’s but 243’s are quite good.

Here is a list of mechanical parts I have compiled so far:

1. Mercruiser Stock bell housing cover works just fine, early Alpha 1 large back opening or cut the hole bigger.

2. Step Dowel Pins may be needed to align the flywheel cover to the engine. Have some step dowels machined 0.62" on one end and 0.704" on the other. About 1" to 1.25" long splitting the length between the two diameters.

3. Considering a Hardin Marine aluminum flywheel.

4. Drive coupler is from a 7.4L 454 Mercruiser with the round mounting plate with six bolt holes in it. I believe this will be better than a 5.7 for hp ratings etc.

5. Engine Mounts ICT billet LLC part number 551628. $$35 eBay and some mercruiser motor mounts to dial in height angle and vibration. eBay $30

6. MARINE engine depot. Has crank mounted water pump. Johnson f6b-9 pump and adapters
Part # 512601- crank balancer adapter $69
Part# 527018- bushing $4
Part #302391- pump support bracket $69
Ordered the pump on Amazon- $135


7. Will reuse the factory serpentine belt setup for water pump, alternator, and power steering.

8 Edit: NOT NEEDED! May need to put a bracket in place of factory a/c compressor. This will allow a mercruiser impeller water pump for the closed cooling system. I’m hearing different things on the bravos having water impellers.

9. Closed cooling system for heat exchanger of antifreeze and secondary one for power steering

10. Hardin marine LS exhaust elbows and riser kit.

Note: this is just about how to marinize a LS. I have an entire other list of things to do to the engine first. We will go through that too as we go. And we will need to cover the outdrive portion too.

Bravo is a very good drive and can easily handle 500HP but the real rating is in torque (most folks can't/don't do the conversion). If I recall correctly a Bravo 1 can handle about 550 ft-lbs and a Bravo 1X can handle about 650. Alpha starts falling apart 350-400. Bravo and Alpha use the same hole but the Bravo has 2 additional bolt holes. You will need a water pump with a Bravo since they do not have an internal one. Here is some info on the evolution of the drives: https://www.go-fast.com/Mercury-Merc...uction-Changes

Make sure you use a marine alternator since the automotive ones are NOT ignition protected - ignition in the bilge= bad day.

Definitely go closed cooling and delete the VVT. Make sure you have a cam that gives low end torque (truck style) so you get better economy.

Like the Chevy small blocks, all the LS motors have the same block externally and just change bore/stroke. I see you have a free 5.3 but think about a 6.0 - maybe a L96 or LY6 if you can find it (even though those have iron blocks - it only adds about 75 lbs) or an aluminum 6.2.

Make sure you put on a remote oil filter. I would use aluminum exhaust manifolds with replaceable anodes. I have a source for those manifolds somewhere in my computer if you want me to run it down.

Yes I agree completely on the alpha’s. I was going to go that direction with about 400hp but a bravo is near me and I just need to get it.

Hardin makes aluminum elbows and risers with dry joints.

Headers: https://www.hardin-marine.com/p-1045...-53-60-62.aspx

Of course I’ll be doing the closed system. VVt is already gone but I need to tap and die and install set screws.

I agree on a big truck cam. Need torque down low, decent mid range, and high end power for when all out. So many options on cams is frustrating. Didn’t have this when I was a kid. If you can recommend one that’d be awesome.

https://www.hardin-marine.com/p-1096...-cam-only.aspx

Looking at compcams and Texas speed too.

I agree a ly6 would have been great but Trust me on island prices and availability. I was originally told it was a 6.0 but no such luck. I looked into boring it out to 6.0 but can’t be done. You could overbore it but not sure it’s worth the hassle given what a Ls cam, heads and tune will do. I’d have built a .383 stroker but this fell in my lap. I figure it will make 500+, should be plenty.

As someone who has a 350 MAG MPI, I was curious. The specs for the LMG that I could find are not high performance- cast pistons, powder metal rods and cast crankshaft. That said, I don't know anything about LS engines.


What sort of revs are you thinking?

Idle to 6500 I doubt I’ll get it out to 7k. The 243 heads are pretty good, I’ll port them, shave them, and put new springs and guides in. Maybe new valves if polishing seating etc is not enough. Cam will change the timing. It has a TBSS (same as ls3 intake). It’s a garden variety gen IV. But can be quite powerful and a good beginning point. I’m going to be trolling not much else. But it’d be nice to get where I want when I’m in a hurry.

The big difference besides distributor and direct port injection is the top end. Most 350’s required lots of work on bottom end to make power. LS blocks are (mostly) all same except for boring. That means throw a cam, intake, set of heads on you have instant power. Getting stuff here is the problem. I can’t tell you how much stuff never makes it here. So we have to figure it out, if we’re not rich.

Check out 3:36. Doubt that’s my cam. But that’s a pretty close setup to my goal.

https://www.youtube.com/watch?v=sbw8JFQ5KE0

You said you're getting a Bravo 1? I have a Bravo 3 with 2.20:1 gearcase. And with the 5000 RPM 350 MAG MPI.


But the Bravo 1 maxes out at 1.65:1 which may make prop selection a challenge if you want to make power by going to 6500? Also, a cam that works at 6000 RPM might not want to troll very well? In this case, VVT would be nice if it allowed the high end power you want.



I was pulling numbers from here: https://www.perfprotech.com/blog/tec...-diagrams-5886


Like I said, I could be wrong about this.

I’m not sure which bravo I’m getting. I’ve got a lead on a bravo with dual props he claims it’s a 2, but I thought only 3 had duals?

As far as vvt, compcams recommended removing it when you cam swap and tune. So I’ll be listening to them.

Been a long day pulling the motor. Separating the engine and tranny was a bear. But all’s well that ends well.

https://i.postimg.cc/JyYX3PZd/88881F...123D2B2858.jpg

https://i.postimg.cc/4Kxthr79/081863...958469EA84.jpg

Nonstop rain since Friday. Supposed to rain all week.

This will be a sweet swap, I am about to swap a LSR block into my Camaro (one day if I ever get any free time again) and going to run MPI with Holley EFI dominator set up with the Holley dash. I have seen a few go fast boats with the holley EFI set ups and you could do the terminator x for reasonable money.

Yeah that terminator x looks to be best way to go. I haven’t figured out the gauges yet. I wanted twin lowrance screens tied together on the outboard. But I’m leaning towards just analogs now. I just want this done.

Sounds like you have a great project too. Don’t forget about that throttle body... I’m going cable drive. And a 102mm vs 92mm adds no hp on dyno according to Richard holdener.

I’d get one of those Fast Lsxr intakes if I could afford one. Sharps custom intakes look great too. But I have the TBSS which is identical power to a LS3 intake and the best OEM you can get. I just can’t justify $1k for 30hp.

PS check out that F35 cam from Texas speed for your swap. It won’t work for me but oh I wish it would.

Purchased a Bravo 3 with counter rotating props yesterday from a guy on another island. Had a friend go look at it and pick it up. Seems to be in good shape. I’ll be tearing it down when it comes but $800 was a steal.

https://i.postimg.cc/dht8PynY/51D761...4EF071AC88.jpg

Engine is all the way down. All apart, cranks out, pistons, all of it. The oil galleys have been tapped for the vvt/Afm delete. The holes are 5/16” so a 3/8-16 tap with 3/8 set screws with thread sealant is perfect. Make sure to use thread cutting oil the block is hard.

Tap these pedestal looking things:

https://i.postimg.cc/fSf01z9y/E81852...009DE54025.jpg

But you’ll have to clean this out of everywhere. The valley plate has sensors on it that deactivate these weird looking lifters.

https://i.postimg.cc/q6T3mhgW/402BFD...BEC15ECC24.jpg

https://i.postimg.cc/TK7nR3HW/406D60...728FB1922E.jpg

https://i.postimg.cc/VdFjVRqg/04F3C2...CF2F4F9D33.jpg

Engine will be going to machine shop for the works:
Cleaning
Block decked
Main bearing alignment and honing
Camshaft bearings aligned and replaced
Pistons cleaned, ringed, and checked hopefully not replaced but who knows.
Block honed and overbored if necessary
Heads to be cleaned, valve job, and shaved .030 to bump up compression on 243’s
Gotta find somebody who balances cranks for bob weight etc.

Will post pics when I can.

Took a little while for the first batch of parts to come in.

Engine has gone to machine shop for the works. Will be a couple weeks before it’s done.

Once completed more parts to follow.

Decided on this cam: https://www.michiganmotorsports.com/...nd-gasket-set/

It’s a 223/226 cam. 226 seems to be max you can run on a budget. Problem is you have to worry about reversion unless you have a fully sleeved header and I’m not spending that kind of money. (4-6k). The problem happens when both valves are open and you have a piston drop. It creates a vacuum and can suck the exhaust water into the engine causing lots of issues.

Yea, the terminator x is really economical compared to the dominator or HP. The digital dash is really over priced especially the 12.3" that I got (got mine 20% off on Holley deal days over the holidays). The little 7" display is not to bad cost wise and you can catch it on sale too somtimes but I don't know how well it would hold up to the salt or marine environment.
Far as my build, I would like to do a billet intake but may just end up with a holley high ram for now. For the throttle body I will probably go the 102 or 123mm due to we are trying to support 2000+ hp. I have TKM right now building the rotating assemble (stage 3 LSR) solid aluminum block, Callies magnum crank, GRP aluminum rods, custom full skirted turbo pistons and it will have to top fuel hoops (solid ss fire rings with copper head gaskets). Similar sister stage three engines they have done made over 2300 with a single 98 mm turbo which had a little smaller back side than mine which is a Forced inductions 98mmx116mm built by Jose. Cam is a custom grind spec from Kevin Mullins at TKM for the application running Methanol on billet atomizer 700s. It is going to be a full tilt race motor so not the common LS stuff. Love to do a mild LS in a seacraft though, I think that would be a really good fit for a 25 seafari. Looks like yours will be plenty strong for the 25 with the 243 heads. Should make a nice piece.

Picture and link to an article below of the sister engine. Mine will be based off of it with a few variations...hope to have mine ready this fall.


https://www.dragzine.com/news/john-d...m-dyno-record/

Wow! Bravo 3 could not handle that! I couldn’t agree more on your thoughts on a mildly built LS.

Good ideas on tb. I’m going cable drive. 103 would need an adapter I think.

Agreed on gauges. I’m either going analog or doing a nmea2k gateway into a 2nd display like another lowrance hds7 gen 3. I really like simrad and furuno but use what you got. Analog is in the lead at moment for wallet reasons.

Imagine this for an intake: https://www.ebay.com/itm/SUPERCHARGE...EAAOSwLsRgcOA1

Macdaddyparts makes an adapter for it.

My goal is 500ish. Sharps custom has a nice intake, as does Holley. I have the tbss. I’m considering the fast Lsxrt but that supercharger would be spicy. I’m going to set it up as is and see how I like it and upgrade intake if I want more.

The seafari 25 originally maxed out with twin 351 Windsor’s to make 500. Making it with a single Ls should be awesome. Doubt I’ll get to 500 but 450+ would be nice.

I just want to hear a 500 hp straight-piped (assuming no mufflers) LS in a boat. I bet it will make the hairs on the back of the neck tingle. :)

I expect so. I’ll probably soundproof and heat shield the cover I’ll make for it. And maybe put some inline mufflers to it. But I expect it will sound incredible.

I’d like to have it quiet when I’m out fishing but every once in a while let her rip. Not sure how I’ll do that tho. I can’t find any affordable captains call exhaust setups.

Until then here’s a preview. But mine’s gonna have a lopier idle.

https://www.youtube.com/watch?v=2AVoeVyvws8

https://www.amazon.com/Electric-Exha...ts_id=15726591

Just saying...:D

Sounds like you have a good path or plan. She will be a ripper at even 400hp. 450-500hp even better and easily attainable with the LS platform. I have always been a Gen 1 SBC guy but I do have to say the LS stuff has a much better architecture. The factory heads on them can be just as good as a mile race gen 1 SBC head. The head I am having done will flow 400+cfm but there are several factory LS heads that flow well stock or with a mild port or CNC run can produce some great numbers. If you do a supercharger do the endplate upgrade as the factory in manifold intercooler will blow the ends out or balloon. The fast LSX manifold dose really well and all of the Holly stuff works and preforms really well. A lot of Drag race guys run the Holly High ram but the Fast manifold will fit much better in a boat under the cover. Make sure you post some pictures of yours once you get moving with installing the LS. I have a seafari 25 and against better judgment have twin 200 merc efis on a bracket for mine. A lot of people say not to do a bracket on a 25 and rightfully so but I am going to give it a shot to see if I can make it work. I need to get mine going. She has sat for a few years now.

Thank you both! That exhaust is saved for when I put that thing in. Wow what Amazon has...

I hear you flying on the sbc1. I thought really hard on making a 383 stroker. a block was $100? From junkyard. But I got this running 5.3 for free out of a truck I know and have worked on it for years for my friend.

Free.99 is hard to pass up but I’ve wondered about that ever since. But I’m committed now.

I hear you on that outboard thing I was dead set and you get a LOT of deck space
But the price of outboards, shipping, wait time, installation, and balance issues...no thanks.

My boat guy said he wouldn’t do outboards and said he’d do this. That ultimately pushed me over the edge. Except he wanted me to buy a crate mercruiser. When I told him what I’m doing he started laughing and said I can’t wait to try it out.

No supercharger likely, TBSS first, maybe Lsxrt 2nd, supercharger not likely as they seem to be drying up and not sure I have enough parts that could handle boost. Agreed on Holley high ram and sniper intakes.

So block came back from machine shop awhile back.

The pistons were badly out of spec. Something like .009-.010

Just placed order for engine parts a little over $2k not including terminator x and exhaust manifolds.

Have the following on order from summit:
KGB-mb5013xp Main bearings
KGB-cr807xpn Connecting rod bearings
Slp-h1132cpa pistons, wrist pins, and snaps
Mah-41859cp piston rings
ARP-234-6301 connecting rod bolts
Clo-9-3658tx3 timing chain
Clo-9-5417 timing damper
Mah-95-3561 gasket kit
ARP-134-1003 cam bolts
ARP-134-1501 timing cover bolts
ARP-234-2503 crank bolt
ARP-434-1202 exhaust header bolts stainless
Sdm-pce229-1006 flywheel
ARP-330-2802 flywheel bolts
Sum-htlskit2 ls7 lifters and trays
Sum-141560 trunnion upgrade

Already have arp head bolts and summit brand main cap bolt kit.

Planning on getting exhaust manifolds, raw water pump at marine engine depot.
Planning on getting terminator x 990-505 through Amazon or Holley directly.
Local Mercury dealer is sourcing a bravo transom assy and timeline. Looks like sept.
Outdrive is scheduled for rebuild/reseal 7/26 in shop.
I have a plan for heat exchangers on the closed cooling system more to come on that.

Will keep parts list updated and pics as is relevant.

I love it but don't go too crazy on that build!!!
I think the straight back Bravo 3 is limited to about 450 ft-lbs torque unless you do some upgrades. Another thing to watch is how deep you mount it - I know you can get drive extensions (0.5"-3") but I don't think you can get a shorty lower for the Bravo 3.
This might be useful: https://www.go-fast.com/Mercury-Merc...uction-Changes

Thanks I’ll look into that. Most of that parts list is the heavy duty parts to handle prolonged higher rpm than car engines experience (main bearings, connecting rod bearings, heavy duty bolts, etc). I’m trying to make a how-to as there aren’t many out there and I want a simple list for the next guy who wants to do this.

The dealer was kind enough to tell me merc’s suggested mounting point of 13 9/16” up the framing sq from keel of boat. That’s the center point for the template to cut out drive hole. I’ll need to mark that and compare the centerline of flywheel and the A/V plate on foot to keel. I’ll measure it out and let you guys know how it’s going.

I was told 600hp was max. I was worried I wouldn’t have enough torque but my bravo3 has a 2.0 (we think) gear ratio. We’ll know more once we tear it apart, inspect and reseal it. It’s the older style without the swept back design. My local dealer told me it’s gonna max out around 55-60mph depending on rpm and be an absolute torque monster with dual prop and 20p blades.

The cam I’m planning on running is a tsp212/218. 437hp @6200 rpm, 418tq @ 4800rpm. I plan to high speed troll 13-20mph most of the time. Other than slightly ported heads, and maybe a bigger TB, there are no other power adders.

I’ll be mating it up to the 454 coupling on flywheel to help mitigate the chance of shearing the coupler apart. Those things are pricey.

I think I finally solved the raw water pump mounting issue to the crankshaft. Hopefully I’ll get through to guy I need to speak with tomorrow.

So parts are coming in left right and center. I haven’t taken pics of each one b/c how exciting are piston rings and main bearings? I figured you see them installed.

https://i.postimg.cc/tZ2Sf38G/4809AA...C14CDB82E2.jpg

https://i.postimg.cc/30NSHyH4/35740F...FFABA4CFB9.jpg

Here’s more hand valve lapping.

https://i.postimg.cc/LYHQNCCV/7D8CDD...0DB79808C8.jpg

Using your water pump bolts can be very helpful to install the cam. Also it’s useful to reach around behind to guid it in for the last 2 cam bearings.

https://i.postimg.cc/hhhsnDP9/086D06...49604E8872.jpg

Here’s my 12yo son putting in his first batch of lifters.

https://i.postimg.cc/Cz3mJ30b/0C1C78...60144493E8.jpg

https://i.postimg.cc/wy4kNPFy/357911...67D98221DC.jpg

https://i.postimg.cc/D4WPPgYC/1D66C2...85D325A636.jpg

So the exhaust manifolds come in Monday. The majority of raw water system comes in tonight at some point.

I ended up ordering the exhaust manifolds from Hardin marine b/c they ended up being cheaper. The marine engine depot guy told me I had to pay more for O2 sensor bungs and it was not in a kit. I did however get most of the raw water system there.

So I caught a mistake when I was reviewing my project. And trying to order a Holley terminator x. The timing set I ordered is compatible for a 1x sensor not a 4x sensor.

i 2 day aired a different cam sprocket in. It was a BTR.

Wrong sprocket for my gen4, 58x reluctor 4x cam sensor:

https://i.postimg.cc/wy4kNPFy/357911...67D98221DC.jpg

right sprocket

https://i.postimg.cc/ygZcZRCz/74B23B...CACABD3DE8.jpg

I tried to break my collarbone yesterday so my son is installing the second head under dads close supervision. I was helping some older friends pack and move off island. I had just repaired the bumper on their avalanche. I was up to my elbows in grease and filth due to rain and conditions. I went out back fo wash off. I went one way and mud went the other. My shoulder landed squarely on a lava rock. Boy that hurt.

https://i.postimg.cc/4KMpy5M5/4C7877...F9E4681E79.jpg


torquing rocker arms

https://i.postimg.cc/V0PMBNz0/CCCFC9...49729D1291.jpg


https://i.postimg.cc/dh52Pvjg/5A9230...290B519A31.jpg

https://i.postimg.cc/WDtMsK9z/04BCB1...3B05CB26E7.jpg


the exhaust manifolds are here and look awesome. That’s a follow-up post shortly with more research I did and info that will help the next guy.

So it’s kind of bad news, good news, bad news.

bad news #1. Can’t find a Holley terminatorX 550-905 or 905t anywhere. If anyone can make a suggestion on where to find one or a different tunable system that has a harness, O2 sensors, and supports MPFI. Otherwise, I’ll be waiting until mid-late August (hopefully).

good news, as I was thinking through how the elbows and risers work along with closed cooling it occurred to me that water might be flowing over O2 sensors. That would be catastrophic. I didn’t want to change these out regularly. I see no worries fir that.

https://i.postimg.cc/cv8nMq0g/2E6A85...830600A139.jpg

you can see the O2 bungs here.
https://i.postimg.cc/ZCn3nBQL/DABA2D...1EF376F75B.jpg

water inlet passage:
https://i.postimg.cc/CBv5pJwp/02D4A5...3E3BE16EEE.jpg

exit:
https://i.postimg.cc/QKHt85M9/D5DBDD...6F52E10E2E.jpg
i do have the parts to install a crank mounted raw water pump. It’s kind of cool when you think up an idea to have a machine shop build and then a little discouraging to find it’s already made. But I suppose that is reinforcement you are on the right track. I’ll post those pics and parts when the whole system is here.

Bad news #2- this is kind of painful

the bravo 3 outdrive I purchased needs a full rebuild. Gear set, cone clutch, shims, seals, bearings, everything- but case, props and shafts are done.
I’ve really considered going alpha route but I’m too far in to turn back now and Bravo is clearly better suited for my application.

I was told it’s pushimg $7k for that job before I buy the gimbal housing another 3k. I got the parts list and found a way to trim some costs down. I expect it will be 4.5k-6k. And then the gimbal housing at 3k. A new alpha is under 3k for whole thing and while that appeals to my wallet. I don’t think that is a wise long term choice. But oh this one hurts, ouch really bad…

we decided to go with 1.81 gear ratio. Originally it was a 2.0 gear ratio. We considered a 1.65 but we’re concerned somethings gonna give as that was not designed for these shafts as well as the load on the engine. Given it’s primary role of fishing we decided to play it safe. I have the parts lists if anybody wants them. Partsvu.com says it’s $3k out the door.

Smart move in avoiding Alpha - While it is a good drive up to ~300HP, your motor would destroy it pretty quickly. You might check out the swap shop on OffShoreOnly - I have seen decent looking Bravos there periodically. Think Bravo X if you go that route.

I have given up on getting a terminator x from Holley. They have moved shipping dates to end of October for the unit I need.

I did find the lingenfelter trg-002 that allows a 58x/4x to run on a 24x/1x. Holley only had ev1 injectors and I have ev6 and I thought adding $300 to the 1k price to do something even ling was a little like “I don’t know man…it should work?” Add it about 1400 for this one engine I figured I depin and tune for much less.

I ordered a harness and ecm for $275 shipped. I’ll depin the harness and program the ecm. I plan on HPTuners ($600) unless there is better advice. I’ll just need a pair of O2’s and I’ll be in business.

I made a run stand and here pics as of now. I’m waiting on the new bell housing for the flywheel and starter. Getting a little closer everyday.

The run stand is a 4x4, some casters, a 2x4, some pocketholes and lag bolts. I figure I will get it running and tuned on stand before lifting it up with gantry crane and in.

https://i.postimg.cc/JyZBLQfG/93510F...BB55CC3DCB.jpg

https://i.postimg.cc/5YmYH2NJ/9F9CA7...7F0B09E1ED.jpg

https://i.postimg.cc/Q9DKxTDS/C7B6E0...B8B30913DF.jpg

Should be picking up bell housing tomorrow. I’ll be adding a plywood control plate for gauges and ignition switch to make sure it’s all good. I’ve been trying to figure out the cooling. It’s been kind of pain finding the fittings and hose locally (without getting destroyed on money).

So here it is with exhaust manifolds on.

https://i.postimg.cc/Cnzd74Mm/5BB613...2317A0BAEE.jpg

Problem with coils…
https://i.postimg.cc/z3BLqqwK/914B0E...410445E876.jpg

I’ll have to relocate the coils using ict billet stuff. #’s 551115-01, 551532- don’t forget custom length plug wires not sure which ones yet I’ll use.

https://i.postimg.cc/YGSS2xFM/B5C726...B69B73A453.jpg

I’m working on the cooling system. I’m trying to get a drawing of what I envision but I’m artistically challenged. It’s not going to be cheap… I have a friend that runs a local plumbing shop.

The harness and ecm should be here Tuesday.
I’m working on ordering the HP tuning supplies and fuel system as we speak.

Make sure you put a remote oil filter kit and remote drain valve kit on that - it will save you a ton of time and frustration. Does it have an aluminum oil pan? Oil pan rust-through is a giant problem with deep bilges.

Has an aluminum oil pan that I have seriously coated in paint and primer. Everything’s been or getting painted… Definitely putting on a remote drain kit (flip lever with hose out the drain plug style). I’ve been arguing about an oil cooler (requiring remote oil filter). It’s probably worth it.

EDIT: this cooling plan is bust see new post about this.

https://i.postimg.cc/478KRxWL/LS_Cooling1.jpg

https://i.postimg.cc/cg1KznBt/LS_Cooling.jpg


This is what I’m going for but above shows fitting sizes. I was toying with doing a pipe manifold with 4 inputs on bottom of manifold (already has threaded holes) but think dual in and out will give more flow.

https://i.postimg.cc/c62HRj2n/514607...A53-AEFC20.jpg


Input, suggestions, etc, please.

remember to remove the pressure relief valve and plug the hole. That joker got me when I rebuilt my 5.3 and deleted the afm.

Do you mean the bypass check valve on the oil filter housing? I haven’t done anything there. I suppose I should look into it. Thanks for the heads up.

Hit a snag on dbc on gen 4 engine

E38 pcms don’t support the IAC, TPS connections required for dbc. And I’m not willing to try to figure out a DBW saltwater situation.

So I found the ligenfelter trg-002 which adapts a 58x/4x engine to a 24x/1x harness. You can then use a LS1 stand alone harness and get a pcm from an early 2000’s Ls to control it. I think I’ll end up around a 2001 pcm. I’ll post more data when can on this issue.

Wish I had a bit more time as I’m on the Big Isld. Staying on a coffee farm airbnb. North of Kona(captain cook)Have to spend tomorrow getting ready for a overnight fishing trip with Kenny Lianes on the Vixen! On Tuesday/Wednesday then leaving on Thursday.
Sounds like you have a hell of a project going getting all of the electronic systems to work with each other! Been keeping an eye on your project and the good work your doing.

For sure bro! I’m on Hilo side but I’m heading kona way on Sat. All those guys there are all stars. I haven’t met a bad one yet.

Enjoy. Ahi (yellowfin) is biting and ono (wahoo) is my favorite. I think there is a way forward here without the Holley terminator x. That would solve it all but this should work.

Tanks, eh. N Mahalos for da aloha!

So it’s been awhile since I’ve updated this. I’ve been having a terrible time getting stuff. My wife’s school (and where our kids go) went to distance learning for 2 weeks. There have been a few cases across the campus and they had no choice. My son tested positive. He’s doing ok so far.

So I had ordered a matching gen 4 harness and pcm. That’s not gonna work. So I ordered a stand-alone LS1 harness that was labeled dbc. But it’s a dbw. So I ordered another harness and the correct 12200411 pcm and sent it to Brendan at lt1swap.com for programming.

Here I’ve been able to get the balancer back on. I had to order a 1157-0163 ls7 ($20 Chevy dealer) crank bolt and used about 8-10 1/2” washers to push that thing on. You’ll need someone with a breaker bar on the flywheel.

https://i.postimg.cc/3yj7JwR2/EEB850...2BE19E2BD2.jpg

My plan for the coils won’t work either so I’m thinking of fabbing a bracket to go here or just screw them to transom. Thoughts? I’m making custom plug wires via a msd kit.

https://i.postimg.cc/WdkTC8cW/A354A1...05499257B8.jpg

And here is what the raw water pump looks like when it is bolted down via bracket and crank bolt connector through marine engine depot.com

https://i.postimg.cc/CZpSg8FF/B702AF...72671C49A2.jpg

Well now I’m stuck at home for another 9 days until we all get tested. Eagerly awaiting the harness and parts. Guess I’ll do some glass work and painting as weather permits.

If possible, mount electronics in a cooler, lower vibration environment. So the transom would be my preference.


With respect to the raw water pump. I can't tell where the bracket mounts- is it the block? This configuration means that the mass of the pump is hanging off the end of the crank, as that flat strapping won't support the pump body and in fact may add additional load. I would worry about fatigue failure from vibration.


I wonder if one from something like a 350 MAG MPI could be retrofit?


Or something like this, remote mounted: https://daviescraig.com/category/ele...ater-pumps-ewp

Yeah I agree the transom is probably dryer. And will be less fab work to make an aluminum bracket off the headers.

That electric pump would have been cheaper than my scenario. And probably save hp. But I’m not sure I can return it. This is how ilmor does their Ls motors. I got the kit from marine enginedepot.com and bought the Johnson pump off Amazon.

Here’s closer up pics. No weight bearing on crank but obvious loss of hp.

Mounts to block
https://i.postimg.cc/xNHrRWTy/C40F42...A5BCF96219.jpg

https://i.postimg.cc/Z0yh4yFB/B4BB8B...02934848DB.jpg

https://i.postimg.cc/bD4c1z8w/76C74A...4F406384E7.jpg

Has a flange that the crank bolt goes through and gives mounting point for water pump.

https://i.postimg.cc/0bR1Q2ct/FC30B0...C7CC4FD3CA.jpg

I’ll kick your idea around but I’m getting pretty far down the road here. That’s exactly what I needed a month ago. I absolutely would have used that. But, I doubt I can return some of this stuff. Once wiring is done hopefully can fire it up once pcm comes in from tuners.

If Ilmor makes it I could very well be wrong.It looks a bit better supported than I could make out from the original photos. I would worry about alignment, but it's really hard to tell from here. generally, given the vibration of the system and flexure of the crank, a compliant coupling like a lovejoy elastomer jaw style coupler would be my go-to for a custom design, but if someplace reputable has engineered this, then I certainly can't validly criticize it from my living room 6000 miles away.


Not sure the Davies Craig pumps are good for salt water, although I expect they wouldn't be terrible.


Good luck, this is an interesting build!

For sure. We’ll find out but as far as I can tell this “should” work. Yes I’m not the best photographer. I truly appreciate you drawing attention to a flaw that’s part of this posting.