Originally Posted by Scully
Originally Posted by Sniper
Originally Posted by Scully
Originally Posted by fastmark
I like the fact that the stealths are aluminum and you can run 10:1 compression ratio and and it does not detonate. Can’t do that with iron heads and pump gas very easily.
With flow and all other things equal an aluminum head needs almost a point higher compression to equal the power of the iron heads.


Not true and if you have documented evidence to state otherwise I'd be happy to see it.

Hotrod ran a comparison of an AL head vs an FE head, they saw nothing to support any of the old wives tales about AL needing more compression, or FE being more sensitive to detonation.

https://www.hotrod.com/articles/ccrp-0602-iron-versus-aluminum-cylinder-heads-test/

What I think, and this is only supposition on my part, is that the reason AL heads got a rep for being more detonation tolerant, or even for making more power, than an iron head is that people were taking iron heads designed in the 50's, 60's or even 70's and comparing them to modern design heads that happened to be made of aluminum. I firmly believe that the combustion chamber design and port improvements account for the differences, not the materials chosen.
In NHRA Stock a lot of Mopars changed over to the acceptable aluminum replacements and were very disappointed. Some combos are factored higher with the original iron heads than the aluminum, the chamber CCs must remain the same. Back before all of the aftermarket heads became legal a well known BB Chev engine builder and Stock racer told me the iron heads are faster.


Building to race rules is a whole different animal. You have to meet their rules regardless if that is the most efficient setup. Also, anecdotal evidence, i.e. someone told me, is not documented evidence. I gave you a link to some relevant and documented testing, that is what I am looking for in this regard. Now if you had a dyno run that showed 915 heads made more power than Stealth heads, ALL ELSE being the same, then that would be interesting.

Years ago one of the big name aftermarket head makers ran an add showing something like 50hp gain with their heads over stock heads. If you read the tiny fine print it said compared to stock 305 heads on a 350. LOL, well no chit cherlock as my Dad would have said. Wonder how it compared to stock 350 heads on a 350?