'75 Scepter - 23' - I/O Mercruiser 350
 

I am trying to get a sense of speed/performance of my 23' Scepter with an i/o Mercruiser 350 with Bravo One drive. The other night with two people, 1/3 gas, i was seeing the following:

- 3,000 rpms - 28 mph
- 4,000 rpms - 32 mph
- 5,000 rpms - 42 mph

I have a 1974 23 Tsunami (aka Sceptre) powered by a 350 C.I Mercruiser with a single Alpha outdrive,with a 15x17 SS prop.

My numbers are close to yours(a bit lower) On a normal day with mild wind and water conditions I'm at

2500 RPMS...........22 MPH
3500 rpms............30 MPH
4600 (my wot).......38 MPH

This is with a full tank of fuel (55 gals) 3 people and lots of tackle and a full cooler of fish. and stand up canvas work that restricts speed to a noticeable degree.
not a rocket ship for sure but fine for me. I rarely run above 2500 rpms. The fastest i've ever had it up to was 41 mph.

I get the same numbers on my 23 Tsunami, 350 Merc 4bbl Alpha 1 17P with 12x12 Bennett tabs. Nice boat in the chop & rollers.

Being an older engine, I just bought a 2012 crate 350 Mag MPI (non ECT) NOS.

Will repower this winter and of course interested to compare the performance! I was tempted to pick up a new big block & bravo drive but costs prevailed...

Any issues I should be prepared for? Good transom, replacing Transom Plate & Outdrive. Expect a pwr steering & perhaps a new fuel tank, some gauges. Never dropped in a brand new engine before!