Pump Gas BBC

8SECNOVA · Post by **8SECNOVA** » Wed Feb 02, 2005 8:52 pm

I need to know what are the most important factors that go into building an engine that will help prevent detonation, such as quench, chamber shape and so on. I want to build a BBC that I can race the pump gas drags with. My goal is 8.80’s- 8.90’s with a 3000lb car. I was thinking 598ci or larger with a small shot of spray or maybe even a blower if needed. I was also considering a spread port head versus standard port, but wasn’t sure if the relatively low compression would not let the heads work to their full potential. Any info or suggestions would be appreciated.

idunno · Post by **idunno** » Thu Feb 03, 2005 2:05 pm

The 14 and 12 degree heads would be the way to go due the small chamber size.In a nutshell the engine likes to reach peak cyl pressure around 20 degrees after top dead center.Now due to factors such as chamber efficiency,dome shape if any,burn rate of fuel and even spark plug location and spark intensity determines how many degrees lead time it has to have to obtain that.Pump gas burns fast from my understanding.A large eng with a 74 cc chamber will be easy to work with with a recessed dome to optimize flame travel.