I have the 1969 351W 2V, that is the one with a HP rating of 250. Is that 250 at the rear wheels or the fly wheel? The original set up was a C-4 trans. and 3:00 gears. It now has a C-6 trans. and 3:73 gears. The questions is, does the C-6 hold back more HP to the rear wheels than a C-4? If so, about how much? I'm seeing poor number on the dyno, only 235 HP.