On my '74 350 small block, I put a new intake and carb on it, replaced cap, rotor, and points. Set the timing with rotor pointing to #1 at tdc, and lit 'er off. She fired right up, even though the idle was a tad high. The problem started when you applied throttle; Slowly and it would rev up a little bit, quickly andalmost die, bothended in a carb backfire.Eventually, several buddies convinced us we were 180 out, so we flipped it. At that point, it wouldn't start. We came back a week later, moved the dist. back 180 (where we had it originally) and started at step one. This time, we couldn't get it to light off. There was backfiring through the exhaust, so we adjusted the timing accordingly, and must have gone too far, cause it started backfiring through the carb again. Really cool fireballs!!! We split the diff, but it still wouldn't run. The best we ever got was for it to start briefly, but it sounded too slow, and MAYBE it was starving for gas, but it was really hard to tell. Any help please?
Thanks

 

Definitely sounds like a timing issue. Set the base timing at straight up or where ever you can get it running. Do you have the vacuum advance hooked up? If so, disconnect that to set the base timing. Once you get it running, set the base timing with a timing light.

What carb did you install? How is it setup? It could be too rich, loading up the engine...

 

The vac advance was hooked up, so I will disconnect that. The carb is a Holley Truck Avenger, 670 cfm, electric choke, and we've made no adjustments to it. It's weird that a week ago it wouldidle great, but backfire through the carb, then Monday it wouldn't even start.