Starting problems

[81 gmc]

My 1981 gmc k35 with a 454 and turbo 400 it has a brand new flexplate and starter and a new battery but when you go to start it it will work about half the time other half of the time it will start to turn over and clunk like it is binding up or it will quit turning over comepletly. All of the bolts are torqued to spec and everything it hook up correctly on the starter. Anyone else have any suggestions? 

[silveradosid]

if it was a reman starter, sometimes you have to put in a shim to prevent binding

[81 gmc]

It has a shim in it but thank you for the thought.