Yep, it has an alternator. Could it be the problem? Thing ran fine two weeks ago, then last week it was popping & cracking like it was dying. I have gone thru the carb & replaced everything in it. The plugs are still showing black, but I am wondering if it's because it's not getting enough fire. I jetted it down from 413 square to 401 & 404. It's crazy because I've run the 413 jets for 1 1/2 years, no problem, now it's fowling the plugs. I think it must be electrical. Tried unhooking the tach also.
Could your module in the hei be going bad? When they get weak it did kind of the same thing to me and I went through the carb thinking it was a fuel thing too. If u have another hei laying around then pull it out of that one and try in yours before you go spend the cash on a new one. Just my two cents. Hope it helps.
In a car that is old, you can have a lot of electrical problems, if the stock wiring harness is used. So,for the things that are used for racing, fuel pump, ign etc, they should be hot wired from a good 12v source, like battery, or starter solenoid, to a switch and fuse. This way, you can have 12v where you want it. With a T pin, you can puncture the harness, and take voltage readings. Most race cars are low on voltage, that is why some use 16v.
If you are using a stock HEI with a vacuum adv. the wire's to the module will flex an breake connection so check them also the rotor will burn through I used to put a dab of the die electric grease down in the pocket to get more life out of the rotor be sure to check the cap for cracks and carbon tracking that's my nickel's worth
What I've done SO FAR trying to find the demon. Completely rebuilt the carb. New fuel lines. New fuel pump. Emptied cell to check for dirt, ect. Tried a different battery. New plugs. New plug wires. Double checked timing - twice. Took the dizzy apart & checked it with a fine tooth comb. Nothing I could see. It would almost have to be the coil if it's the dizzy. I borrowed another dizzy from a friend today, so I will try it tomorrow & see if that's it. If not, don't call the fire departmant when you see smoke.
If it is the coil or module I am not aware of any way to test it or to see if its bad. Maybe use ur dizzy with another coil then use another dizzy with ur coil etc. By changing just one thing at a time should help u pinpoint the culprit. I am interested in finding out what it is too. Hate to learn at anothers expense! LOL. Keep us updated