Quote:
Originally Posted by GTO-relic
interesting...what pro stock castings was he trying to obtain, RA V heads ? they were raced in early 1970's in Pro Stock.
or were they trying to find early BBC castings ?
elaborate on what he said about your RA V billet prototypes ?
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To answer your questions: The heads I was desperately trying to find for Annie were the very early Pro Stock BBC based heads completely re-engineered by Pontiac and generically referred to as "Big Chief" heads. What some people don't realize is the basic BBC heads were so extensively modified and improved by Pontiac that they made at least 6 different versions and different castings. None were directly compatible or interchangeable and different intake manifolds, every part of the valve train and the headers were different between versions. The heads Arnie needed were called the "396" castings. Nearly impossible to find. Darin Morgan thought he knew where a few sets were and expended considerable time trying to get a set for Arnie.
With our nitro Ram Air V heads, I had a rapid prototype in plastic and he suggested using 1/2 a dozen different size and shape tubes for the pushrods on the flow bench. To prove the large tube we needed to run a 1/2" pushrod through the center of the port would hurt the flow much less than anticipated. At peak the max flow between no tube and a 9/16" tube was right at 20 CFM on a 430 CFM port. He also gave us some pointers as how much to raise the exhaust port and shape the areas around the guides and the 5 angles for the intake seat and radius for the exhaust. We also reduced the exhaust valve size slightly on his recommendation. Little stuff like that. Back to topic. Sorry if derailed.