Need help with rough running 3rz

I bought a 3rz from an insurance auction a 1996 Tacoma with the 2.7l 5 speed 4wd. I brought it home and swapped a cab and a bed from a 1995 kept all the engine wiring and the ecu of the same engine and harness. While I had the engine out I changed the head gasket and reassembled the whole thing.

I brought it home and drove it around before swapping everything and now that I’ve reassembled it. It seems like I can’t get the timing correct,

I installed it per the instructions and there is good spark I pulled the plugs out and fuel is sent into the air out the cylinder. I also changed the fuel filter

I cleaned the maf and put a known working maf from a different truck.

I’ve also installed a distributor from a known working truck as well as caps and plugs.

It idles fine but during accelaration it feels like it’s a little gutless, and stumbles really bad I opened the air intake box and heard a back fire in the intake system.

no check engine light, and perfect compression across four cylinders.

I’m running out of ideas to troubleshot at this point

update, I ran a timing light and the truck even though I set it at top dead center 12 I clock on the rotor, is consistently on the 15 marker behind the harmonic balancer and not the 0 like I set it. And I had to advance timing on the timing light about 50 degrees before it showed up to 0 on the harmonic balancer
it’s a 1996 Tacoma 2.7l 3rz