rebuild motor now wont start (help)

[leftyokie]

we rebuild motor in my 94 stroke, rings, bearings, gaskets, 1 piston, etc.
now with the motor back together in truck it wont start. 1st try we werent getting oil up top, so we pulled the front off the motor cleaned it all up new gaskets, and we reselled the oil pan. 2nd try now we have oil pressure and fuel. we cranked it with the gp out it primed up. put gp in valve covers on and it will crank and crank tries to fire but wont go all the way. any ideas would sure help we are running out of ideas. Jason