Quote:
Originally Posted by Step Up
So I have this 1974 20 foot Sceptre it has the original 6 in it. I want this boat for a run about only. So I was thinking pull the 6 and go 5.7 or 5.0 but then I was thinking why. I am not building a race boat. But I would like to spruce it up the 6 a bit. Have any of you beefed up a 6 before? As well any one know the average WOT of a 20 I/o with the 6
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I think they are probably one of the best sterndrive power-plants ever put together. Formula and Bertram put "pairs" of them in hundreds of boats and Cigarette used a pair them some of their "fishing" 28's. A single manifold and elbow cut down on the maintainance costs and they seldom developed enough torque to destroy a type one Mercruiser. You could "squeeze" two in an 8' beam hull and still change the starter motors without pulling the engine. They were part of the "Iron Duke" Chevy family of engines. When Mercruiser started using the 302 Ford block "888 Mercruiser" (V-8 - 188 HP) they became a little more popular in a single engine application than the inline six. Still there are many functioning today with marginal mechanics keeping them going.
Pontiac used that 250 CI block and built an aluminum Single overhead cam version with better carb's and put some in Firebirds and their LaMans' or Tempests. That very light motor would make 250 HP, I think out of the box.
I believe you would see something north of 40 MPH with one in a 20' Sceptre. (The 4 cylinder Mercruiser powered SeaFaris would go about 36 MPH) What a great "low budget" Ski Boat. Pelican knows about these motors and drives, maybe he'll chime in.