1989 Country Squire with a 347

[BlackVic_P71]

I know I have an older thread here, but that kinda got lost in the updates.
The 1989 I bought from the original owner in 2013 here in NY, has the standard 20+ years in NY rust.
Since purchase I've done the big brake swap up front, a 1997 rear end with 31 spline axles and a mass air swap with a 347 with a forged bottom end.
The plan is to supercharge in time for the Hot Rod Power Tour in June...if that happens with all this virus stuff going on.
Here are some pics
2013

2015
Also, along the way I made some unique turn signals for the front

2019








As you can see, it currently has a 2005 P71 airbox/MAF on it and was tuned for that by a local shop.
I was supposed to go tomorrow and get the supercharger tune done, but I did something 2 weeks ago and suddenly it won't run, I put on the oil pump that this motor came to me with(Melling 68A), yesterday I put back the standard Ford oil pump back in.
I have a real bad misfire that is creating a backfire in the exhaust and it's very difficult to get running at all.
It's down on power since half the cylinders aren't firing...I have swapped TFI modules with tested good ones, swapped the cap and rotor, swapped the computer(along with the chip) and it doesn't help at all.
What are the other things I can check?

[Tiggie]

So we were running okay and then the oil pump change and now the no fire situation?

Does the problem side spark at all? Edit: just saw your other post that you have spark and fuel.

I’m leaning towards a timing issue. Verify #1 TDC on compression stroke. Check firing order and see what it will do with the SPOUT out.

[BlackVic_P71]

So we were running okay and then the oil pump change and now the no fire situation?

Does the problem side spark at all?

I’m leaning towards a timing issue.

Timing as in the timing chain?
I checked exhaust temp and it appears at least a few on both sides of the motor fire, a few primaries read ~100degrees while others were ~350 after running a few minutes.
When I did the oil pump, I had issues getting the driveshaft in, distributor came out a few times.
Sent from my SM-G975U using Tapatalk

[Tiggie]

Timing as in distributor timing.