I bought a book at Barnes & Nobel today. It has V8 engines from the mid 1900's through the late 70's. In the Buick section it has all casting numbers and other related infomation. Under the head description, it states that a 1970 Stage 1 head had larger valves (stated the sizes of them), then it says that they also had the larger runners which were the same as 1967 430 heads. I thought the heads were the same as normal 1970 heads, but with a larger valve and better springs. Is the book wrong about Stage 1's? It also talks about a few Tunnel Port heads that Buick sold for drag racing in the early 70's, and it mentions the Stage 2's. What were the Tunnel Ports?
I was always under the impression that Stage1 heads were regular 455 castings opened up to fit the bigger valves. I believe they would open up the pockets some what at the same time. I think the actual runners were the same though. I think the tunnel port heads were the Stage2's. They had round exhaust ports didn't they?
The book states: There were special D-Port Stage 11 heads built by Buick, but because of casting problems, only 75 to 100 sets were built. Buick also built Tunnel Port heads for drag racing. They also said: The 1970 Stage 1 heads had larger runners (same as those used on 1967 430 engines) and larger valves. 2.12 intake and 1.75 exhaust. They must have been mis-informed.
THERE WRONG. stage one heads have different valves and the valve seat area was unshrouded, then the stage 1 springs were installed also.
