Swapping 95 5.7 competition ski to 98 chevy vortec

[Spencer36]

I purchased a 95 ski ray with a mercruiser 5.7 competition ski motor. I have a good 5.7 vortec from a 1998 z71 that I want to replace it with. What modifications do I have to make to do this? The current motor is carburated and the vortec is tbi.

 

[alldodge]

Re: Swapping 95 5.7 competition ski to 98 chevy vortec

Welcome to the forum but ................................
Auto and marine engines are not the same and a direct swap should not be done. Autos need the torque built up as RPM increases, marine needs the torque to start off and then level off. Ignition components are not the same because auto stuff can cause boats to blow up and really ruin your day

 

[Spencer36]

Re: Swapping 95 5.7 competition ski to 98 chevy vortec

Welcome to the forum but ................................
Auto and marine engines are not the same and a direct swap should not be done. Autos need the torque built up as RPM increases, marine needs the torque to start off and then level off. Ignition components are not the same because auto stuff can cause boats to blow up and really ruin your day

What changes do I need to make?

 

[alldodge]

Re: Swapping 95 5.7 competition ski to 98 chevy vortec

Use the block and heads from the new motor, use the cam and everything else from the marine engine.

 

[Spencer36]

Re: Swapping 95 5.7 competition ski to 98 chevy vortec

The intake manifold won't fit. Can I put a carb on the tbi intake or do I need to get a different one?

 

[79Formula]

Re: Swapping 95 5.7 competition ski to 98 chevy vortec

Get a vortec specific manifold. Edelbrock will work fine. The vortec heads really made my boat come alive.

 

[Spencer36]

Re: Swapping 95 5.7 competition ski to 98 chevy vortec

2 barrel or four? Going to be cruisen half the time and sking the other.

 

[matt167]

Re: Swapping 95 5.7 competition ski to 98 chevy vortec

The Vortec should not be TBI. They were CSFI with the spider injector setup '96-'99. In any case. Just use an Edelbrock or other manifold for Vortec heads and to keep it cheap, you can use the stock carb from the boat., No need to swap cams, as truck cams are very close to marine grinds, but also the truck cam is a roller, and the marine cam will be a flat tappet. You do need to change everything else to boat stuff and also the core plugs need to be swapped to brass plugs.

 

[Spencer36]

Re: Swapping 95 5.7 competition ski to 98 chevy vortec

Thanks for all the help. Ill let ya know how it turns out.