Thank you Paul, I was about to blow a gasket here! Ok, 85 was the first year for a roller cam, hydraulic roller cam. 84 and earlier had flat tappet hydraulic camshafts. 82 and later had 50 oz inbalance and the 81 and earliers had the 28 oz. I may be off a year here correct me if I'm wrong and I will change it. 94 was the first year for a hydraulic roller cam 351, very rare to find, as they only made these for a few years. All other 351's were flat tappet hydraulic. Ford has not used a solid flat tappet camshaft since 1967 with the end of the 289 hipo engines. Earlier 260 V8's some had solid camshafts I believe. Hope this clears up things.