[craig]

yes, it will bolt up. Just remember that the 89 engine has a 50 oz imbalance and the 70 is a 28 oz imbalance. You must use the proper flexplate, you can buy an aftermarket 50 oz flexplate to fit you c4 convertor. If you must change the harmonic balancer, same rules apply and you can buy a 50 oz balancer with the correct offset for your application