Not 100% sure lol, I'm guessing between 10:1 and 11:1. Sounds pretty mean when she's running and I have to run premium now. I have a 268 cam, adj cam gear, long tube to 2.5" exhaust (no cat, just muffler) and now that offy manifold and 390cfm 4 barrel holley. Should be a pretty solid set up once its all tuned. I was goin to work on it this week bit my front main seal on my dd bmw hoopty went out so I ended up doing a bunch of work to that instead lol. Went out to Hollister today in my buddies 83 though to get me fired back up so I should have it running this week.
