Popping sound from exhaust at low speed....

[CudamanTom]

Ok now I want to hear this pop.
Can you take a vid of the car idling and then juicing it to say 2500rpm and still getting that pop?

I'm going to go out on a limb here and say:

The two things that really come to mind is
1) some sort of vacuum issue
2) bad electrical issue (connectors, plugs, wires, bad MSD box, etc)

B,
I'll try to get a video this weekend.
Just to clarify, it doesn't pop in neutral at idle or any other speed. Only when I put a load on it in various low RPMs.
The wires and plugs are new. Not sure on the MSD box. One thing I haven't done is replaced the cap. I might try that.
I also adjusted the holley carb per the holley website. Got a little more vacuum (8 to 9in). Still popped.
I got busy yesterday and forgot to take a video. I will try this weekend.
I do appreciate your thoughts and input you've been providing VERY much!!! 

[HP_Cuda]

Tom

No problem. Whenever you tackle something like this I think you already know, start from the cheapest solution towards the most expensive.

The vacuum issue can be coming from the Holley as well, how old is it, when was the last time it was rebuilt, etc? Probably a moot question since you probably bought it with the carb. If that is the case, has the car always popped? Did it do that when you bought it?

B

p.s. You know one of these comes to mind as you can hook it up and see everything in action (plugs firing, timing, curves, etc)

[CudamanTom]

B,
Yep, the carb came with the motor so I know nothing prior of it's condition. I saw and heard the motor run but not drive (car was being dismantled). Just sitting there running prior is the same as now. Didn't hear the popping. But it wasn't being driven either.

I do have a 850 holley on my other cuda 440 (also has a cam, not road ready at this time) that I did see driven in passenger seat so I might take that carb off and swap it out. This would rule out the carb I would think. Cheaper and faster to do.
I think cap and carb will be the next things I do to isolate the probable causes. I hope.

[HP_Cuda]

Swapping the carb out is a great idea. If you know it's a known good quantity then it's an excellent idea.

I have done this numerous times.

Cap would not break the bank to try. Is there major pitting on the inside? Have you pulled any plugs to see if any of them are fouling more than others?

Just throwing out ideas,
B

[Strawdawg]

Did I miss a compression test on all cylinders?

[CudamanTom]

Did I miss a compression test on all cylinders?

Steve, good point. I have not done that yet. I will get a compression tester and check each cylinder.
Thank you for your input.