Hey Chevy gurus! Im in desperate need of some serious advise. Im having the worst time with my 1981 Pontiac firebird. I built a 305 sbc, the year is according to sbc.com is a 1980 to 1984 305 block. Now I have tried serveral different starters and replaced the flexplate. When i built this thing I was using my brothers 73 350 starter and had no probs for about a year. But then it took an unforfunate turn and shatered the nose cone. So I bought one for a 1984 305 chevy camaro z28. Autozone told me this was the correct one. Now my car will not start. Ive tried the shimming and I get nothing or a loud clank and grind. I live in an apartment complex and have had several complaints against me for this noise. I need to know if any one out there knows the exact shimming sizes that i can get to fix this prob. If i cant get it right this time Im affraid Ill be evicted out of my home, not to mention this is the only vehicle I have right now. So please chevy high can you help me?  

Whats up!! Chevy made two different flex plates. The one is 168 tooth, the other I think is a 153. I have only ever used the 168, but if the nose on the starter is mis-matched, I'm shure there would be a ruccus like you described. I had a distributor seize in the full advance position once, and it sounded like pigs being killed till I found the problem. One easy way to tell is pull the power line off the distributor and try turning it over. If that does it, pull the distributor, gut it and clean where the advance shaft rolls on the main shaft. If not, check that flexplate. I think the 168 tooth is 15in. diam.  

I have a thread posted for Chev Starters. It has some info.
First question: What really happened when you "took an unforfunate turn and shatered the nose cone"? Did you run over something or how did that happen? I am suspicious of that!!!
Do a gear clearance check. Unhook battery ground (self protection). With your torque converter inspection/dust cover off, check the clearance between gear and flexplate. You remove the solenoid (more work) and actuate the drive mechanism by hand and see how the  starter pinion gear engages with the flex plate ring gear. Any parts house has starter shims if needed. I have never needed to shim a chev starter but some sound better than others depending on gear clearance. It is then a process of elimination to search for answers.
Keep us posted of progress.