I'm not sure about what the requirements are for a marine motor, but one of the most restrictive pieces on our 302s is the E7TE heads. Mounted on a larger cubic inch motor will make them even more inadequate. The main difference between the 2 heads (E7s and E5s) is the combustion chamber size. The E7s have a smaller combustion chamber, this will raise the compression ratio.
For a factory boat that you want to keep factory (mpg) then at least run some gt40 heads, may even consider polishing the ports yourself they should run around $350 just make sure you wont have any other $ in them or they will be a waste as you could get EDelbrocks for $800
This is an older thread, you may not receive a response, and could
be reviving an old thread. Please consider creating a new thread.
Ford Mustang Forum
A forum community dedicated to Ford Mustang owners and enthusiasts. Come join the discussion about performance, builds, modifications, reviews, engine swaps, classifieds, troubleshooting, maintenance, and more!