i'd say timing is way off.. by you pressing on the gas and cranking it over, your letting a little bit of fuel throught the pump by doing so, then your ignition will fire that fine but then once again will be off once that is out of the system.

it won't be your exhaust gasket/intake gasket.. that doesn't do that.

also when you did the swap did you take off the head to make sure it was at TDC (top dead center)???