(1964 C-10 with a 283 and the previous owner put a 3 speed auto in it. I got the truck in the spring.)
I have been trying to put on a starter for some time and finally I got a real mechanic out to look at it and he said that all he could figure out was that the flywheel was on backwards. All of the new starters that we tried didn't engage far enough on to the flywheel. One guy also mentioned the flexplate. I am no mechanic other than simple things so if anybody wants to shed light on this situation feel free to.

Thanks