Cast iron & aluminum intake & heads.

[ericcarr2000]

Ok, I have a question. I have a 1990 7.4 mercruiser motor that pretty much Is bone stock. It currently has the cast iron intake and heads on it. Ive been contemplating switching over to an aftermarket aluminum intake and heads. Who on here has an aluminum intake & heads on their craft, have you had any problems with the setup vs the cast iron one?

 

[NHGuy]

Well you can do it and they do perform better. They run a bit cooler so you can run more compression and timing advance without detonation. They are lighter, and the most advanced designs are available in aluminum.
BUT, not for salt water unless you have closed cooling, they corrode quick in salt.
There are loads of big block experts on offshore only. Go over there and search the topic. You won't even have to start a thread, there are dozens.