Distributor issues?

[Oystercopy]

Hey guys.

I've had a runnability problem with this car for about 4 years. Threw a whole lot of parts and money at it over the years. The engine has had a "stumble" for a long time. It runs very rough and even misfires/backfires a lot during acceleration. I've replaced (literally) everything on this engine (ignition-wise) except the distributor itself. Ignition coil is a new MSD, so are spark plug wires, plugs, rotor and cap. Ignition module was replaced also. The problem (seemed) to start when I had the new cam kit put in. I don't believe it was anything in the kit that caused the problem (itself) although we did have a weak valve spring that has since been replaced.

I understand that distributors can go bad, I've just never had reason to replace one, and I'm also not sure I need to get one that is specifically for this engine and even the cam? Do the shafts wear out, causing issues? My car has the upgraded electronic ignition so no points.

Any help appreciated!
OC

 

[Challenger RTA]

KISS. Keep It Simple Sam. Variations on the phrase include "keep it super simple", "keep it simple, silly", "keep it short and simple", "keep it short and sweet", "keep it simple and straightforward", "keep it small and simple", "keep it simple, soldier", "keep it simple, sailor", "keep it simple, sweetie", "keep it stupidly simple", or "keep it sweet and simple"

Been there done that!
Distributor related
Firing order correct, I check mine a number of times and thought it was correct. Low and behold the 10th time or what ever, two were switched. It happens!

1 You changed the distributor cap but is it good. Lets say it is. Spark jumping in cap.
2 Are the spark plugs good? I would aways suspect that. Small cracks can't always be seen.
3 Are the spark plug wires good? They can be check with a meter. that dose not always indicate there bad. A megger would if you have one. It's not fool proof, to much area to check. I have found them by looking at the engine running in the dark. Not that you'll see a lightning show. Look for halos or small arcing.
4 Distributor clamp ground.
5 Air gap set correctly for reductor and pickup.
6 Coil getting the correct voltage all the time. Bad connections. Bulkhead connection, wires, switches. Bad coil, correct MSD coil? Temporarily. Put a jumper wire from battery to resistor run wire side only. Blue. Take it for a drive. Try on alt stud too.
7 Battery and alternator voltage good?
8 Vacuum advance working.
9 Yes the distributor busing does go bad. Check for play.
Borrow one and swap it out, then you know!

 

[Challenger RTA]

new cam kit put in

Wiped a lobe?

It runs very rough and even misfires/backfires a lot during acceleration.

Choke not opening correctly? Accelerator pump? Carb issues.