So my '85 T/A has been out of commission for quite some time (2014 was the last tag on it). I've done a fair bit of work on it since it's been down, and now I cannot get it to light off. It'll backfire out of the exhaust anytime I try to start it. Things that I've done since the last time it ran (which was stupid rich):

Fuel injectors (new 19#)
Fuel pump & filter
Fuel pressure regulator
BBK 52MM throttlebody (TPS voltage reset)
ECM
Battery
Porting of the intake manifold, runners, and plenum.
Car is an 85 Firebird 305 TPI with a 5 speed swap. It has ~15k on the swap, so that shouldn't be the issue.

I've verified I've got spark, fuel pressure is good, I haven't checked to see if the injectors are firing yet (to do this weekend) but if I give it any throttle, the backfire out the exhaust gets much bigger. I think I'm so far out on timing that I can't get it to fire. I've verified that the timing mark on the damper if directly after the #1 intake valve closes, so I don't think I'm 180 out. I did have problems getting the distributor to seat where I wanted it to when trying to stab it in, which is why I think I've got timing issues. My initial question is, what should the timing be set at when trying to crank it over (est wire disconnected)? Plan is to get timing set by spinning the motor over without the fuel pump/injectors running so I can keep my hearing. I'm open to any other suggestions as well.

 

You didn't mention if you replaced the 6 year old gas in the tank.

 

Yes I did. Drained the tank, inspected for any rust (didn't find any) put 5 gallons of fresh gas in it.

 

I'd think you don't have the distributor in correctly. If it's backfiring, would mean you have fuel...i/e injectors are working. Seems you also have spak, but not at the correct time needed, hence the backfires.

Start back over, pull #1 plug.

Put your finger over the hole the plug was in and rotate the engine by hand-i/e ratchet on the HB bolt.

When you feel compression, look down at the HB and continue to rotate until the mark on the HB is lined up 6 or so BTDC.

Then pull your distributor cap and see if the rotor is pointing near/at #1 that goes to #1 plug.

If not then pull it and correct it.

Above assumes the ring on the balancer hasn't slipped and you have the plug wires routed correctly via the firing order and distributor rotation.