[chevybar]

Hey guys, I found a 5.7 today that is from a trustworthy person, that being said, swapping from the 4.3 to the 5.7, I think the coupler will work, bell housing and all else. I will need manifolds, Will I need to move motor mounts? Anything else I might not have thought about, Thanks in advance! Barry

[ColoradoDiablo]

Drive Gearing

Larry

[chevybar]

Larry , I have thought about that, but with the increase in weight, new exhaust manifolds, moving motor mounts and changing gearing, there is not enough horsepower increase, in my opinion, maybe 30, with added weight . My best choice maybe 4.3 after all. It would be easier ? Barry

[ColoradoDiablo]

IMO , way easier Chevy. If you had a donor boat it would be different , but there are going to be a whole lot of little things to deal with.
Stick with the 4.3 and maybe aluminum intake , and aluminum manifolds and You outta be around 220-230 hp.

Just my 2 cents worth

Larry

[chevybar]

Thanks a bunch! I may buy the 5.7 anyway, it is a good deal, never know, I have a list of other things to do before an engine anyway, electric hatch actuators work ,no power to switch, bildge pump the same, put the transom assembly back in, bleed trim, it goes on and on, you got to love this stuff! Thanks for the info, hope to be able to return the favor. chevybar

[Motoxxx43]

Not to highjack a thread but where would one find aluminum manifolds? GLM seems to be the name that keeps coming up but I have not read about performance on the V6.

[ColoradoDiablo]

These are the ones I put on my 4.3 Moto. They are GLM. I love em , but I only had them on for about 28hrs run time before motor went south. It had nothing to do with the manifolds , bad build I guess.
Anyway they improved bottom and top end on my 4.3. I'm at 6-9000 ft and definately noticed improvement
As long as you aren't running in salt or brackish water I'd go for em!!

Aluminum Marine 4" Exhaust Manifolds Elbows Risers 4.3 262 Mercruiser 59225 kit

[Motoxxx43]

Good to know. Those were the ones I kept running into. I had no idea what model my motor would need- 3'' or 4'' or ? For under 600 that sounds pretty good.

[ColoradoDiablo]

Measure the outside of your riser to y pipe rubber connector. If it is around 4" you got 3" risers. If it's around 5" you got 4" risers.
Thats just a quickey , but should tell ya.

[ColoradoDiablo]

If you have a 4bbl carb , it's got 4" risers.