a friend of mine did head work for nascar race trucks with alum small blocks. he said they were good for 600 or so hp. i said mebbe they should run em in boars. he said iron blocks are better torque producers. AL for horsepower. this was 10 years ago. now they are seeing marine use more, but not a lot. as far as closed cooling, i can't see putting raw water through an iron MK IV big block. small blocks are cheap and easy enough to replace.

If we are talking big blocks unless you are looking to save weight every dyno shop and pro engine builder I have ever dealt with or talked to tells me they make less hp ALWAYS, Smitty

The block or heads have no idea what is in it.

Yep, ring seal goes away pretty quickly. I really wanted to go all aluminum but was advised against it by those who have built quite a few endurance engines. Works fine for a drag application though.

Not true...heat distortion causes cylinder walls to shift and effect ring seal and therefore loosing H/P, also head temp changes with alum VS iron and also changes H/P...

the main reason most dont use aluminum block is cost,cast aluminum blocks are becoming a thing of the past,and a billet block normally cost around 10 grand prepped and ready to go.

Has anyone tried to run silicone silicate in a closed system to coat the internals with liquid glass before running them with an open cooling system? You can buy this stuff at the drug store, and you are basically coating the cooling system with glass. Works very well when running copper head gaskets to seal the coolant leaks. Old time racer trick. Run it through the cooling system when you are on the dyno and get it heated up real good so it solidifies and coats everything real good.

Until the cylinders start to dance around and lose ring seal/ distort and wear un-evenly (talking BBC and old school sbc like I mentioned in my post). Years ago I spent a fortune on a splayed cap, Dart aluminum SBC rocket block, had a custom drag pan built for it, raised cam tunnel for tons of stroke, etc, etc. Talked to 4 different top name machine shops about doing the finish work and they all told me the same thing-why did I want to build a motor thats going to make 25-40 LESS hp to save a few pounds??? Now, a motor engineered SPECIFICALLY around aluminum from a clean slate, sure but all these bbc aluminum blocks are basically someone pouring aluminum into a iron mold with cast iron cylinder liners, Smitty