I need major help

[71440charger]

alright here is the problem i just put a 440 in my 71 charger changed from a 318. when i try to start the car the starter gear just hits the end and does not spin. so i put four diferent starters on the sar and the same thing happend well the motor turns over just fine with a wrench so i know the engine is not to tight. so i took the starter off grounded it and turned the key and the gear just hits the end and does not spin i changedout the starter relay and redone the grounds so now i have no clue what the prob is. thanks.

[Nacho-RT74]

does the starter motor work fine out of the car ?