Dirk,
What size tires (diameter) do you use?
My car weighs 3100, has a 2.88, 25.7" tires (335/35/17 in the back) with a C-6 and about a 2000 rpm stall converter. Except for the trans running too hot at the track - soon to be fixed with a 1600-1800 rpm mud truck converter - it's a dandy combo.
6000 rpm is 154 mph, at 3000 half that or 77 mph, good hwy cruising speed.
It will blow street tires away at any speed up to about 100 with 46/54 weight distribution if I whack the throttle (try this at the track, please). Track tires stick nicely and don't seem to spin too much under race track conditions.
Rear wheel HP is around 410 after the C-6 gets finished with the engine's output.
It still runs nicely in traffic, idling or even in a really slow parade.
Pretty satisfactory to me for a truck motor
Carl Rossler built the trans and FTI is building the torque converter as I type - at least I hope so...
Regards,
Tom