Especially points these days are getting to be junk, couple that with crap ballast resistors, wiring harnesses and condensers, it makes for a ton of fun... Ive seen it all in some of my GM projects. It almost makes me want to switch to electronic. 

I’ve also had points in the past that hung open and didn’t close on time. Timing was jumping all over and took a bit to find. I filed it under the same heading as the condensers, off shore junk. Drove me crazy, but some days that’s a short trip.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

There have been several Postings regarding bad NEW Condensers. Offshore Junk Try another Condensor and check the little Ground wire from Points to Distributor Housing. May look OK but breaks where U can't see it. I would also check the Timing Chain skip as suggested in prior Post.

  

Always check the last thing you worked on. I would recheck points and condenser connections.

You say it has 20, 000 mi on it? With the head problems you found, do you think it could be 120,000? I would be suspect of the timing chain jumped. Remove the passenger valve cover and place the engine at TDC # 6 cyl. Lay a straight edge on the spring retainers of #1 and check to be even/level. 

Collector                                                                                                                                                                                   I had a similar problem a few years ago and found out it was the harmonic balancer. The ring had slipped and would not stay in time, hard starting and back-fired. Found a used one at a "classic car" salvage yard and it still working good.   Just a thought.
Jim

Hey guys I'm kinda new here but I'm really stuck on this, it keeps backfiring threw the carb and exhaust. Here's some back info on it. I have a 64 f100 with a 292 with 20 thousand miles on it found it in a feild been there since 87. It is completely stock I've been fixing it up it was leaking oil out of the valves like hell so I pulled the heads and had positive stop valve seals installed and hardened valve seats for the exhaust.
Did a new distributor and oil pump because someone had put the oil pump driveshaft in upside down and tack welded it to the distributor never seen anything like that before. Has a new coil, plugs, plug wires, points, cap and rotor. I rebuilt the carb.

So before the heads sometimes it felt like the distributor wasn't advancing and it would bog out. Now after the heads and everything it ran pretty good I drove it 50 miles that night to Reno to help my brother with a duece he bought. Then the next day it started right up drove it another 50 miles then parked it over night again. Then that night it never started again found the points had closed up so fixed that try to drive it around the block and it just kept backfiring threw the carb.

Alright so I compression checked it to make sure it wasn't the valves I got 120 on all cylinders cold and it didn't leak down any. Ran the overhead again the valve lash. It was advanced 10 degrees so I reset it to tdc and then it would hardly run just kept backfiring out the exhaust. So I advanced it again about 5 or 7 degrees now it only runs with the throttle half way open and takes turns backfiring threw the carb and exhaust. I'm getting no vacuum reading on the dwell meter and the plugs look fouled like it's running really rich.

Do you guys think it's the carb or the timing because I'm lost I use to be a car mechanic I'd do heads and transmissions everyday but I've never done anything this old.