Hi I just replaced my transmission and torque converter in my 68 firebird from a powerglide to a th400 and found out that my flexplate had stress cracks in it- so i had the shop replace that. When I get the car back from them yesterday, it started right up but after I got to the gas station and filled up, it just made a terrible scraping/grinding noise when i tried to restart it. It was that same noise you hear when some guy in a rice rocket doesn't know his car is already on and tries to start it. I tried several times to start it with the same result, but after about 5 times it started. It sounded like it was having a hard time disengaging the starter when it actually started. I have no idea what is causing this, but it didn't do it before i had the flexplate changed. I was thinking that maybe my starter got toasted by the hooker competition headers i put on, but it has never had this problem in the past and the headers have been on for several weeks. Please help- because I am so stumped thanks,
Brad

Sounds like you need to shim the starter. Shims come in a 2 pack or 4 pack and you have to put them between the starter and block, through the bolt holes. Start with 1 shim and try it for a day. If the starter still does not engage flexplate fully, try another shim.

Could also be the solenoid not fully engaging or releasing.

Shims $5-6 Solenoid $10-15. Never hurts to have a spare solenoid on hand.

thanks banshee, I called the shop who put in the flexplate and they said if I brought the car in that they would shim it up for free. I think I'm just gooing to replace that old starter while I'm at it- thanks again.