I pulled my 1973 mustang convertible 302 engine and it was pretty tired after all, I have a friend that has crate engines and was able to get one for $650.00. Thing seem to be bolting up pretty well but I was told I might have to change the harmonic balance and flex plate to the 50 once balancer and associated flex plate. Engine number is E5AE C3B which tells me it is an 85 year 302. Does anyone know for sure which balancer is require?