I have a 1984 small block from a Mustang installed in my 1971 Mustang Grande. I have installed an Edelbrock performer intake and carburetor. I know that the distributor and waterpump are form the orginal 1971 block. I would like to replace the harmonic balancer that is currently installed. No timing marks etc and looks over all worn out. I was looking at two different TCI offerings from the Elastomer Balancer seriers for the Ford Small Block, external balance eaither the 28oz or the 50oz. After readling I found that the 50oz is for HO 302's. So how do I tell if I have a HO 302 that would require the 50oz?