Just throwing out an observation, if I had weather I would add that as well. That said, there's a reason a 600hp SB is usually quicker than a 600hp BB. Rotating assy weight is going to matter less with a Powerglide that only loses 800rpm on a single gearchange, but it matters quite a bit more with a manual trans car that loses 2000rpm on each of it's 3 gear changes.
Grant