starter problem

[694X4]

Ok this sounds simple but for some reason it's not. The whole story: Truck caught fire from a short. Put in used harness from firewall out. new starter, battery, voltage reg., alt., flex plate, and I have used every shim combination possible even putting shims on one bolt only thinking that maybe it would do some thing but it still skips teath. I went and ordered the bracket thing from a dealer...still skips. I can get it to sound perfect then after 10-15 starts it starts skiping again and the whole process starts over. Oh and it is a 69 gmc 2wd 350/350 hei if you need more info let me know.