454, yamaha 7.4 liters engine to replace a 5.7 liter engine, Now what ??

**dompie99** · 09-09-2016, 09:06 PM

My cousin has a 33 feets long boat with a 5.7 liters OMC carbed engine. now this POOR thing has a lot of problems to get to plane if it ever does, the cruising speed of it is about 22 to 24 mph, max speed could be something around 28 to 30 mph.

We saw, on the web, a 454 Yamaha engine with all the marine stuff on it.

I have a few questions here.

Could it replace without a 1000 items to correct a 350 ( 5.7 liters ) engine ??

what should be done. I know about outboards but inboards, Not a great deal.

**Capt.Insane-o** · 09-10-2016, 01:05 PM

I guess so, but you'd need, omc manifolds, risers, y pipe, depending on which ignition system, possibly shift cable bracket and etc etc. On a 33ft boat with a single a cobra isn't going to live too long up against a big block. I'd bravo 3 package it at an absolute minimum.

**dompie99** · 09-10-2016, 05:26 PM

so in other words, the LW will not survive the torque of the Big Block ?? shoute....I think we will forget this project unless I get a Bravo complete really cheap

**flabum1017** · 09-10-2016, 05:33 PM

if it's a Cobra Drive, it will puke, but if it's a king cobra or the cone clutch cobra (volvo penta style) then it will be ok.... but..... good luck finding parts for either the cobra or king cobra if they puke. I would try finding a complete engine drive package with either a Bravo 3 or Volvo duoprop