All Small Six Help! Did I just screw up my new build?

[pmuller9]

…#1 piston is at TDC, drop the dizzy, line up the mark for first spark plug to the rotor.

TDC on the compression stroke. You have a 50/50 chance

 

[awasson]

TDC on the compression stroke. You have a 50/50 chance

Yep, my super power is to drop it in 180° out first time, every time.
I might as well not even try to get it right

 

[Frank]

Thanks, I’ll try plugging PCV and double checking distributor and spacer. I’m pretty certain I dropped it the right way…#1 piston is at TDC, drop the dizzy, line up the mark for first spark plug to the rotor.
Will come back to it later this week and reinstall everything…

I was using ported vacuum on the front of the carb. But when I was starting it now, vacuum line was disconnected and plugged at the carb.

Verify that you are on #1 compression stroke, not exhaust stroke. both #1 rockers should be slack. Backfire in carb is late ignition timing 95% of the time. If you turned the engine with the distributor out you may be on #1 exhaust cycle, the ignition timing is 180* late if so.
Vacuum advance is not a factor at cranking speed.

 

[drag-200stang]

Make sure that you do not lose the oil pump driveshaft when taking the dist. in and out and it stays in place.