Backfiring suggests you're losing spark, not fuel. If you're using the HEI distributor, you might suspect the pickup coil around the distributor shaft. The wires on it flex each time the vacuum advance turns the plate and eventually those wires break off. A clue that works sometimes is to disconnect and plug the vacuum hose. That will prevent the plate from turning. If it doesn't start at all or if it runs continuously, suspect that coil.

caradiodoc

Answered by caradiodoc (expert)
17,276 answers provided

Thanks for the reply. That was our first assumption so I replaced the distributor coil about two months ago. The old one looked ok but I replaced it anyway. I will definitely give your suggestion a shot. Could it be possible maybe that the coil is good but perhaps the ground screw or threads have corrosion?

Response from Badjer21
1 question asked

Nope. The screws just hold it in place. They aren't used to ground it electrically.

I suppose you could have an intermittent module, but they really didn't cause much trouble compared to the stuff on newer cars. You might try a different ignition coil too.

Look too at the toothed reluctor wheel to see if it is cracked. I read a lot about that but I've never actually found one myself.

caradiodoc

Answered by caradiodoc (expert)
17,276 answers provided

So I finished my carb rebuild to no avail. As the distributor coil is already new I guess my next move is to replace the distributor itself. I was contemplating going to an MSD HEI anyway so now I have my excuse.

Response from Badjer21
1 question asked