Intake swapping?? 4.3l omc

[Earp]

My doner 4.3 engine came with a 4 barrel rochester and a high rise Intake, will it be a big pain to try and use it vs. the stock low rise 2 barrel? My boat is an 87 20' cadorette. Not sure if any slight gain in power will be worth it?

 

[Bondo]

Re: Intake swapping?? 4.3l omc

Ayuh,... Donno how Difficult it'll be, but a Good runnin' 4bbl. yields 'bout 20hp additional or so...

 

[Reinell-BRXL-191]

Re: Intake swapping?? 4.3l omc

Well, one thing, Is the donor engine a marine engine? If yes.. then if the 4 barrel is in good shape.. you can use it... if it is not a marine engine.. then no, its dangerous to use it..

One concern is HP vs gas economy.. You will see a slight increase in HP like Bond-o said.. but you will also see a dramatic increase in fuel usage.. so, if the boat performs well, and can get up on plain and runs nice with the 2 barrel, it would probably be to your advantage to not use the 4 barrel... but, if you can use the extra HP - go for it...

 

[run2car]

Re: Intake swapping?? 4.3l omc

High rise on stock 4.3?? Not sure about that.

 

[Earp]

Re: Intake swapping?? 4.3l omc

High rise on stock 4.3?? Not sure about that.

Feel like getting a bit more specific? Thats kinda why I posted this. The donor engine is marine and had the 4 barrel/highrise combo running fine when it was pulled.

 

[Bondo]

Re: Intake swapping?? 4.3l omc

High rise on stock 4.3?? Not sure about that.

Ayuh,.... High rise is a relative term,...

It'll be taller than the 2bbl. intake, 'n considerably shorter than what a Hot Rodder would call a High rise....

 

[Howard Sterndrive]

Re: Intake swapping?? 4.3l omc

Some Astro Vans and some other 4.3's up to 1987 had factory hi-rise qjet intakes - cast iron. sort of a mid-rise, yeah... maybe 3 inches higher than the typical mercruiser/omc cast iron manifold.
They were pretty neat to look at and work pretty well on boats once the EGR thingy is blocked off etc.