Mercruiser 3.7 exahust manifold

[yamhoss86]

I have a 1982 Mercruiser 470.
Do i need to swap risers if i change the exhaust manifold to the 1988 exhaust manifold?
Will the 1988 exhaust manifold fit the 1982 block.
Thanks.

 

[Eric 3.7LX Alpha 1]

Re: Mercruiser 3.7 exahust manifold

The head hasn't changed. So both manifolds will bolt to it. If you are changing from a cast iron manifold to an aluminum one, you must also replace the riser. They won't be interchangeable, the riser bolt pattern is different.

 

[Bob_VT]

Re: Mercruiser 3.7 exahust manifold

Suggestion........ whenever I do any manifold work I spend a few dollars extra and get a tap for the bolt holes in the block. It is a great practice to clean out the threads in those bolt holes before you re-assemble

 

[achris]

Re: Mercruiser 3.7 exahust manifold

Suggestion........ whenever I do any manifold work I spend a few dollars extra and get a tap for the bolt holes in the block. It is a great practice to clean out the threads in those bolt holes before you re-assemble

And that should be standard practice for all threads in heads and blocks!