My old combo was the same as Bison's stock motor and GN1 heads. the CPT 66BB I was using was a P-trim with a .85 housing. The first full 1/4 mile pass with this combo netted a 10.89@124 @ 20-21# boost 1.61-60 foot. The converter was a local 9x11 unlocked and slipping terribly on that pass. TCI calculator showed approximately 16-17% slippage and a trap RPM of 6075 with a 27.5" tire. I am sure it would have gone 10.40-10.50 @ 127-129with 24-25# boost and a good converter.
Datar