I'm not saying anything, to throw water on anybody's ideas. I just wanted to comment, on stuff from the late 60's thru mid 70's. At that time I was on a crew part time that ran a modified, with 427 with hi riser heads. When the tunnel ports became available, the car owner, wanted to try them. The lap times, never matched the hi-riser. The driver said the hi-riser had a broader power curve. Now I'm talking 3/8, 1/2, and 3/4 mile tracks. The car was later sold, and replaced by a new car with a 500 inch BBC. At Thompson speedway, the old car with 427 hi-riser was brought along to make the deal with it's new owner. The BBC had problems during practice, and the owner decided to pull the car. The new owner suggested that " why not run the old car with the Ford". Which they did, the driver won the consi, and starting at the back, worked his way to a 4th place finish, behind 3 BBC that we're all near 500 inches. Just for some history, some might enjoy.