Hiya,
I got a problem now that's really kicking my can!
I'm getting a pop through the exhaust that's totally random at any time, any speed, cold or hot, night or day, sometimes loud, sometimes soft, but always VERY annoying!

Here's all I did so far;
Replaced the distributor cap and rotor.
The old center electrode looked like it caught on fire so I replace the center electrode with a low resistance one.

Replaced the coil.
I thought perhaps the electrode burning up may have caused some kind of short. Nope!

Replaced the plugs and wires.
The old plugs had a couple fouled ones and one wire was arcing on the header.
New plugs are Bosch and the wires are Taylor as I had before. I also added heat shields on 4 wires that may be too close to the headers.

Checked and reset the static timing, 10 BTDC. Checked the mechanical advance for sticking and vacumm advance for a ruptured diaphragm. Nope!

Rebuilt the 1406 Edelbrock carburetor. Made sure the accelerator pump worked. Vacumm is at 12 at 950 rpm. Normal for the cam.

Checked and re checked firing order, YES plug 5 and 7 are correct.

Checked for wire arcing at night. Nope!

Re checked the distributor cap again.

Checked valve lash on rocker arms and re adjusted just in case.

Did a nominal check for vacumm leaks Nothing obvious.

The only thing now i'm wondering is if I have too thick oil in the car. I'm running straight 50w and I don't think I had this problem before I changed oil. But from what I read 50w is good for HP since the leakdown is slow. BUT! I don't know. The lifters are not anti pump up and i'm wondering if they're not pumping up the lifters to where they leave a valve open too long.
I did notice that there's not too much oil getting to the rocker arms and the first front lifter on the right side didn't seem to have too much resistance when adjusting it but seems to work when running.
I checked the springs and they're all ok so it seems.

The only other clue I got is there's a slight whistling at the carburetor at idle that isn't always constant but mostly constant. It goes away off idle.

The popping comes mostly from the right tailpipe but it's popped through both pipes on occasion.
The exhaust does have a "T" crossover pipe. So, I don't think it's muffler baffles.

I don't think it afterburn from a rich mixture since the popping happens before engine warm up.
I didn't re jet the carb. The only change was a AN connection at the carb fuel inlet.
I checked float level and drop prior to assembling the carb.

At first after all my repairs I thought the problem went away but now it's back with a vengence.
The car has lots of power and acceleration, In fact it ran like a striped ape but the popping noises on the freeway are getting up my wick now.

Does anyone have any new suggestions? I'm stumped!