I'm putting a built 347 (28 oz balancer) roller into my 1970. I'm using the 67 C4 that came with the car that I build up to handle the additional HP. The new coverter will be a 10 inch. 10.5 bolt pattern. Same as old flexplate. Will not be for racing - weekend street. I'm assuming okay to use old one but would like to get some confirmation from someone more knowledgeable than me. thanks