stop dont do another thing until you find out if you have free travel in youre crankshaft. take a big screwdriver and force the crank forward then backward in the block you should have around . 010 or better. if you're not absolutely sure you have this clearance do not attempt to start the engine. i would have to guess that you some how got the input shaft in wrong or it is wrong part and its forcing you're crank shaft forward into the block and locking engine. if it has play turn the engine over by hand easiest way is with alt nut in reverse if this is all good then you may of just got unlucky and starter decided to go bad or you pulled a wire out. jump the motor on the starter and see if it turns if ya only get a huge spark ya got a bad starter. good luck