[Dirty Harry]

I'm running a 351W with a .030 overbore, Edelbrock Performer manifold, camshaft, arburetor and double row timing chain. I use Autolite 45 plugs, fired by a MSD 6A box, Blaster 2 coil, and a Duraspark distributor. I replaced the pickup in the distributor a couple years ago. I don't know how to test it or the MSD box.

This weekend, after a spirited run through the gears, the car began running horribly, missing and backfiring at idle. I pulled the valve covers and found all the rockers and valve springs to look fine. I compression checked all the cylinders and found them all above 180#. The MSD cap is almost new and looks good. The plugs are fairly new and all look good, with a light tan color, tinged in pink. The gap is .042. The Taylor 8mm wires are, admittedly, very old, though. I have ordered new ones. I haven't pulled the distributor to look at the gear yet. I haven't sampled the fuel yet, either. The filter is clean.

I'm wanting to find my solution quickly, as I have plans and reservations made for a weekend trip in the car. What am I overlooking, or what else should I check?