Are all the 8 pin ignition modules that same?

[Fast355]

I'm still pretty new to this so a couple questions up front:
A) Are 048 and 369 both the same type of modules but different versions?
B) Seems like I should look for the 369 module. If so, How do I identify it and is it plug and play?

My configuration: AMC 401, fresh rebuild, Performer intake, Comp Cams 268H, 16197427, 454TB, $0E

My symptoms: timing is set to 0, with timing plug pulled timing stays steady at 0 and it idles well. I also get a CEL when setting the timing (I assume this is normal since my computer does not see the module, and once I plug the module in, reset the computer, the light goes away). I plug in timing signal, timing bounces between between 18 and 20 (both watching at the damper with a timing light and at TunerProRT) and it occasionally surges. Give it any throttle and it quickly goes to about 32 and backfires like mad. Symptoms are the same in open or closed loop.

Recently, I was running well but had low oil pressure. I rebuilt my oil pump (involves pulling the dizzy), now have awesome oil pressure but these symptoms. I have not verified my TDC marker since the oil pump rebuild and plan to do so soon but was also going to throw a module at it while I was in there.

Anything else I am missing/should consider?

When you are looking at an OEM junkyard module the 369 and 048 will clearly be stamped on top. Many fullsize G-vans got the 369 module in either a 4.3 or 350 V8. A lot of the TPI cars had the 369 as well but those are much less common then the vans in the wreckers.

As for your issue, for older slower burning heads it sounds like you may not have enough timing advance. Retarded ignition timing can cause the engine to backfire. What was it timed at prior to the distributor being removed? I have not messed with a 401, but I have a 304 and a 360. Both of them liked 12-16* of initial advance with 22* centrfical from the HEI and about 10-14* vacuum advance. At 3,000 rpm with the vacuum connected it is not uncommon to run 50-56* of timing. Not knowing what you have for a timing map its hard to say what your initial should be set at. If it is still a stock GM TBI timing table, I would bump your initial advance up to about 12* and test what happens. The AMC V8s usually make best power with 36-38* of timing advance and a stock TBI truck rarely has more than 22* at WOT. Also the timing maps on the GM TBIs have a very slow advance rate and often negative timing values at high kpa and low engine speed.