What type/brand of starters is he buying? How did the starter fail? Is it a straight bolt pattern or offset bolt pattern starter? Is he using the starter brace that goes between the back of the starter and the engine block? When you buy a starter, you have to realize that there is a difference between a $60 brand new starer and a $120 remanufactured starter. I just had a starter fail on me, the commutator came apart and destroyed the brushes. I refused to buy any starter sold at Kragen because I know they are crap. I hunted down a Delco-Remey remanufactured starter and bought that. Delco is the original manufacturer of GM starters. I have never had to shim a starter, either. If you buy a good starter, built by the company who designed it, it will fit right. I also recommend you use offset bolt pattern starters because they are stronger and don't necessarily require a brace. I use an offset bolt pattern starter with no brace in my truck and have had no problems. GM made 2 starters in that year that will bolt up to that truck. There is a short body and long body. You can tell the difference because the connection between the solenoid and starter will have an extension in it. A short body starter might be too heavily loaded while trying to turn that engine over and burn itself out.