[Dr. Eric M. Schiffer]

Here is a better understanding of the tunnel port heads. The article should help you understand why most racers went back to the Ram Air IV heads.

The Ram Air V program was spear headed by Tom Nell and Herb Adams in 1968. They wanted a SCCA Pontiac to run in the program. Their 1971 - 1972 Trans Ams would have been a high compression 455 with Ram Air IV heads. These would have been rocket ships to run head to head with the LS-6 Chevelles.

High compression 455 Ram Air IV is what the Blackbird began with in the March 1971 Popular Hot Rodding article. The Ram Air V heads just did not work as well as the IV's. Tom Nell designed the camshaft for the Blackbird. These same Ram Air IV heads are still there.