J78, Good question- It looks like a matter of things stacking up: * I have your weight down as 3310, almost 300lb heavier than the 68 Camaro. * Your T350 helps, but you also have a taller rear - and the T350 does draw a little more power than the Glide. * The engine is down maybe 15-20ftlb across the board, a matter of smog tuning mostly. That pretty much does it.