Poor driveability

I have a 1976 Nova with a 1973 307 in it. I also just put an Edlebrock 600 CFM carb on it. I started it up and it sounded great while it was idling. But when I took it for a ride it seemed to be hesitating and when I re-timed it and took it for a ride it backkfired and continued to hesitate when I accelerate. I'm not sure if I timed it correctly or not. I warmed the car and disconnected and plugged the vacuum line on the distributor. I then adjsuted it to 8 degrees before TDC. The idle mixture screws are turned out 2 1/2 turns from all the way lean. I talked to a guy at my local parts store when I picked up the carb and he said that if I turned them out 3 turns that would be best but when I did, the car shut off on me. Does anyone have any ideas on how to get my car running right? Please help.

I would crank them both in, then out 1.5 turns. Start it up, use a vacuum gage, turn in each one until the vacuum falls off, back them out until you have a maximum reading. Do it one at a time, then double check it.

Does the carb have vacuum secondaries? If so, make sure the line doesn't leak sucking air. Do a general check for a vacuum leak, with the engine running, cup one hand over the air horn, if the idle picks up, you have a vacuum leak. The carb gasket could be upside down, which is an easy fix.

Bob

Thanks Bob. This seemed to make things better. No vacuum leaks and I made the adjustments on the carb. It got better, no more backfiring, but I'm still getting hesitation when I floor it. When I made these adjustments, should the distributor vacuum have been connected or dosconnected, and is that where the vacuum gauge should have been hooked up to if it was disconnected from the distributor? Also, I only had about 5 Hg of vacuum, does that seem right? Thanks again

Unless you're doing the actual timing, leave the distributor vacuum hooked up. When you do unplug it to do the timing, take the line off at the vacuum advance and stick a golf tee into the open line.

You can hook the vacuum gage up to any vacuum port, vacuum is vacuum, period. Your vacuum reading sounds really low, unless you have a stout cam in the motor. It should be around 13-15 for a healthy motor otherwise.

What is your timing like? The motor might need a little more advance for the carb. Try like 6-8 BTDC, any more and you'll have hot starting problems and have to use premium gas only.

I don't know much about the carb that you have, can you change the jets or the power valve like a Holley?

Bob