Help!!! won't start....Mechanic please!

WAIT....TIME OUT....

Exactly what did you disassemble to change your rear main seal????

lets start there
OK I pulled the engine, removed the the crank... to replace the seal and of course the timing chain and distributor and yes the oil pump drive gear was out. but I think.... I put it back together right.... I'm douting myself now and trying to remember it all..... NO WASN'T DRINKING THAT EVENING.
it is backfiring when I try to start it.