Been reading all the threads on 500+ inch motors with AFR, Dart, Canfield etc. heads and the power to be made is awsome. I would like to hear some real world numbers on a set of ported Iron Eagles or Merlins. Unless someone can convince me that aluminum heads will survive in salt water. I can't imagine having to fill up the already tight engine compartment with two heat exchangers and all the additional plumbing to go to fresh water cooling. Dart told me they can do the same hard coating on the water jackets that they do for Mercury. Has anyone had any experience with this stuff?

Viper,
Have you checked out the Edlebrock Marine heads? They are hard anodized with inconnel exhaust valves. They look really nice! They come with either Oval Ports or Rectangle ports. I did an article on them for FAMILY AND PERFORMANCE BOATING MAGAZINE, March 2002. Flow figures in the Edelbrock catalog.
Dennis Moore

There is nothing wrong with iron heads. The negatives are that they are heavy, and they are a tougher material to machine for porting. One thing to remember is that iron holds heat more so than aluminum so the compression ratio needs to be selected accordingly. I don't have any HP numbers to share, but I would guess a fully ported Dart 345 iron eagle will be within a few HP of the aluminum counterpart 345 pro 1. Jim V could shed some light on this subject I am sure.

I remember seeing somewhere in the last month that some motors put together by World/Merllin had a HP rating difference of 20 HP between cast & alum. HP ratings were in the 500+ range.