is there any advantages or diadvantages of putting aluminum heads and intake manifold on a small block engine

Hi 26,

Check out this add. Hopefully it will answer your question.

http://www.chevyhiperformance.com/te...38/index3.html

Another consideration would be where the boat is run, salt water or fresh. If it's in salt a lot the aluminum will corrode quickly.
I've read that you can run a little bit higher compression with the aluminum due to the heat dissipation.

Iron heads with the same air flow and chamber shape will make a few more hp. Aluminum heads can use and need a little more compression, are easily modidied, REPARIABLE, lighter, more detonation free, etc. Some heads and intakes can be bought with anodizing that will all but stop corrosion even in salt water. Air Flow Research is one source for great heads with anodizing.
Almost any aftermarket heads and aluminum inake will add considerable performance to a small block, especially if you add a good camshaft.