I put a reman 302 (suppose to be mid 70's model engine) with C4 tranny. I using the flywheel that was in the trunk of my comet when I bought it. After putting the engine and tranny in, the car has always had a annoying shimmy to it while driving. I've changed out my harmonic balancer and made no difference. So now I'm wondering about the flexplate. The numbers on the counter weight are C4AE-6375 B ASSY.
If you've got a 70's engine, it'll be the correct imbalance for it. Could be a driveshaft vibration you're feeling. It's more of a buzzing vibe than an engine imbalance which feels like a shaking, almost like what a wheel/tire combo feels like when out of balance or out of round (tire coming apart)
