5.7 mercruiser heads question.

[Jake222]

I have a friend with a 1998 mercruiser 5.7 efi with cracked block. My question is if I swap the engine with same year post 95 motor with vortec heads(an automobile engine) did the heads that mercruiser used in the 1998 or post 95 goto vortec/same design as well. I’m asking to know if I need to look into an intake as well. I don’t want opinions on if it works or not because I’ve done it before on a pre vortec mercruiser That runs great. Just never done a post 95 swap and was wondering if the heads are the same as what I can get. I don’t have the boat yet so I haven’t pulled the intake to compare and will get my answer that way just would rather know before.

 

[Jake222]

I found my answer through motor # lookup. They are the same design. Just need to use brass freeze plugs.

 

[Scott06]

1996 and up vortec heads will be the same and intakes will swap over. If you are swapping an automotive engine not only the freeze plugs but head gaskets and water pump need to-be marine. If yku are using a truck engine the cam will work for marine applications, but car engines have different valve duration and lobe separation angle need to swap for truck order marine cam. Can likely take the cam and roller lifter out of the old engine if needed.

 

[Scott Danforth]

no such thing as a freeze plug. there are core plugs to get casting core sand out at the factory.

to marinize a block, you need marine head gaskets, marine cam, the forementioned brass or stainless core plugs and a marine circulating block.

 

[achris]

I'd also knock the cam bore plug out of the back of the engine and fit stainless or brass. (nothing gunna spoil your day faster than that plug rusting out...)

 

[nola mike]

I'd also knock the cam bore plug out of the back of the engine and fit stainless or brass. (nothing gunna spoil your day faster than that plug rusting out...)

I found my answer through motor # lookup. They are the same design. Just need to use brass freeze plugs.

Check them before you change them. Mine were all brass on a 4.3l from an '01 blazer.