Richard66ford

I have a 66 mustang coupe with a 1981 302, and a three speed manual trans. I bought the car last summer and and started right up until about last month. we started it up and it would grind the ring gear. we replaced the starter and it worked for about a day then grinded the ring gear again. we replaced the ring ring gear now and i put the starter on and got a grinding noise. The flywheel has 157 teeth and that is what the starter is made for. any help would be appreciated.