New problem with my 428PI. I recently put in a rebuilt date coded distributor with points and condenser replacing my after market electronic ignition. I also put in a rebuilt correct ignition coil. I don't think it has been even 100 miles since it was done. I went to a cars and coffee about 50 miles away 3 weeks ago. The car ran fine on the way there. On the way home, the car started running horribly and backfiring from the front carburetor. It got worse as we nursed it home. At idle in the garage, it is a rhythmic front carburetor pop every 2 seconds or so. I replaced all plugs and plug wires, reconnected the old ignition coil, changed the points and condenser and checked for vacuum leaks all to no avail. Any ideas as I am running out?