ok i tried to start it...the engien is trying realy hard but its backfiring into the carb. I just checked my spark plugs and they are correct.

 

Plug wires going in wrong order or the distributor is installed 180 out.

 

have you had the distributor out to make morley think it's 180 out? what have you done any repairs or trouble shooting? if so what? does it have spark? fuel? compression? if you can answer yes to all 3 them it should start, providing you've not done nay repairs thast you never mentioned.

 

is the engine stock? or have u done and mods
happend to my truck, put a 4 barrel and an intake on a 302 (kno its ford but im tryin to make a point) and kept stock exhaust manifolds, so there was a lot of air comin in and non going out