I have a 351 Cleveland engine that just wants to backfire through the carb. Checked timing and it appears to be accurate. The intake is a performer with a Holley carb, I think it's a 4160, but I just can't seem to make it sit, the intake, on the engine, without sealing properly. I've tried to seal the intake with black rtv at then ends of the intake won't seal. Replaced the intake gaskets with edlebrock gaskets and didn't use valley pan gasket, still can't get her to seal. It's leaking along the rear, right side intake matting service. I'm lost at what else to do. Help!

1. Could be damged valve seats or valves. 2. You've checked the dist. timing, how about the cam. Might be that the chain jumped.. I don't know about the clev but it happened alot on my buddies 302. Looks like a pain to check the timing with the front on those beasts.

Thanks for the feed back. Milling the intake was a thought. I didn't rebuild the engine, but I was told when I bought the car the engine had been rebuilt. By the way they are 2v heads. Block numbers say it's a 1972-73 Cleveland. I did notice the choke isn't reacting to adjustment. Power up the choke and it didn't move. Took an ohm meter to the choke coil and got continuity. I did notice the ground wire is grounded at the carb housing. Not sure if this is the correct place, but ground wire has a hole that matches up with the screw that goes into the side of the carb. What a head ache.