Hi,
I just finished installing an edelbrock 600 performer carb (1406) and a performer RPM intake on my otherwise totally stock 1972 350. If I step on the gas more than about 1/3 of WOT then the carb backfires and pops once or twice and then begins accelerating normally. The timing is set at 7 degrees BTDC. Any ideas as to where the problem most likely is? should I look first at the ignition/timing or would it most likely be a problem within the carb? Any suggestions are much appreciated.
-FJ

check the plugs to see if they are fouled - that's a nice easy place to start. I ran that same carb (1406 elec choke) one a bone stock 350 in my 750 for a while, never had a backfire issue due to carb calibration - it worked perfect out of the box.

Thanks for the advice Lev. I pulled the plugs and they are pretty black, and appeared to have a small amount of oil on them. Where should I go from here do you suppose? The plugs in there now are AC delco R-44T just like the manual says to use, but do you think a hotter plug would improve anything? I am not too educated on spark plug diagnostics, so any insight is appreciated. Thanks again!
-FJ

Edelbrock "Carter" style carbs are such a pain. Make sure that you are using a pressure regulator, as they don't like more than 6.5 PSI - even a stock fuel pump can push almost 9. Even with the plugs being black, I would suggest using a vacuum gauge to set the idle mixture screws. Hook the gauge up to your power brake hose or to the big port on the front of the carb on the base. Adjust the drivers side screw until you get the highest vacuum reading you can. Adjust the other screw likewise, then adjust the first screw once more. This should balance things out & help to eliminate the stumble. I always adjust my Quadrajets this way & never have any problems with stumbling. I don't know why Edelbrock keeps pushing the "Carter" style carb, because they are very troublesome. I prefer the Quadrajets - which make excellent power & give some semblance of gas mileage to boot, & the Speed Demon carbs. The Speed Demons are awesome - albeit pricey - but they are worth the money.

I love the Edelbrock carbs, I keep trying to get the Holley 850 I have to run right, and no luck...but I bolt on the Edelbrock 750 or 800 and they both run great...They are one of the easiest to run carbs. I would look again at your ignition timing...bump it up a little, but make sure you're not too far advanced...if not advanced enough, it will pop like that. Or, it could possibly be the carb...try adjusting the mixture screws like advised, but a rich mixture wont usually make it run like that. Sounds more lean if anything...Do one thing at a time. John

Thanks a lot for all the advice fellas. I will try those suggestions and report back. BTW sweet ride Jonny O. Thanks again!

Have you checked the accelerator pump? Maybe you're getting too big of a shot.