For all the 273 Naysayers

perfacar said

hi, in S/S , the port volumes and chamber volumes have to be at the stock sizes. like wise valve size also. comp ratio and top of piston have to be same
as came stock. in other words, it has no 14to 1 comp ratio. the heads are reworked to get highest port velocity and flow needed. the stock carb is required. the fact is, its fuel curve in carb that makes it go fast. class racers are very good at finding the hidden power in a combination. they're not parts changers like most guys. any one can change parts to go faster. just food for thought.

Click to expand...

Yea brother! Not sure what is legal now, but compression ratio at minimum NHRA blueprint was 11.5 to 1 for the 273 hipo. When my friends were into Super Stock and Stock class racing: cam / valvetrain; intake manifold; Pistons; Rings; and Exhaust was all you could legally change. Valve job was limited. And if it even looked like you did any porting on the heads, you were disqualified. It was supposed to show the upper limits of what a basically stock engine could run with just those changes. That was a long time ago. I was always amazed how fast they would go. As I remember you had to contact NHRA to get the rules and acceptable casting numbers and blueprint specifications for your engine.