76olds

Could use some help here. I have read some other threads and timing seems to be the issue.
I have a refreshed 350 olds due to a bent connecting rod my fault before storage to much oil down the carb before it chocked out.
Here we go replaced rod , did a valve job new stock cam and chain put motor back installed 2 1/4 dual pipes from manifolds installed a shift kit all good . The mechanic said everything else was good otherwise. Paid $3000 .
fair anuf
This past summer I myself with my limited mechanical exp. Installed an edelebrock performer , edelbrock 600 carb, taylor spiro pro 8mm , bosch plugs, accel cap, rotor, coil and module . It runs great not the power of the line I was hoping for would like put a little rubber down but maybe headers will give it more .
The problem is the backfiring once in a while on start-up . If the car sits for the week I have to pump it oh 10-15 times to fire and at times it backfires , could I have a bad coil or module something else please let me know you guys are awesome here.


Thanks Eric

MDchanic

If it just backfires when you first start it after pumping the gas a bunch of times, then it's probably just the raw gas you pumped into it igniting.

First thought would be "Pump it less."

- Eric

J-(Chicago)

I'd guess timing. Maybe It's firing back into the intake.

Set Initial to 12 degrees and see if it runs better.