Car is a 68 with a 289 and a 4speed. I've got a flywheel with 164 teeth. At the time I got it I didn't know there was a 157 also. With there being two different ones and I not knowing which is on my car at the moment, are they interchangable? Friend of mine that works at Autozone says they are the same diameter, but the teeth are a little closer together so will wear out the starter. I'd like your advice on if I need to locate a 157 or I can use the one I have. Thanks for any insight you can give!