Here's more of what is more common with bolt-ons and driveable cams.
http://www.youtube.com/watch?v=4L4qVjAB5jg

http://www.youtube.com/watch?v=DUYFFsKFEpk

 

The trans will make a big differance as well as how big the converter is and if the converter is locked or unlocked during a dyno pull. My car made 393 when it was a 6 speed, I swapped in a 4L60E and a Yank 4000 converter. With no other changes I made 376. However the car went nearly .5 quicker. I am a cam/bolt on car and I run 11.8's @113-115 mph. Heads and short block are completley stock.

 

That would explain why my Z28 Dynoed so low HP wise. Full-bolt on and everything, but it was an A4 with a Raptor 3k stall. It put down a ton of torque though- 400rwtq. I never ran it with DRs to see what it could really do cause I feared the stock rear, but like you said, a good stall can knock off .5 tenths.

 

I've heard converters will cause you to put down really high torque numbers but lower hp numbers. Is that generally true?

 

That was the case with my converter...330rwhp vs. 400rwtq.

 

It depends on the STR (stall torque ratio) of the converter, but generally this is true. BTW I am pulling consistant 1.5x 60's on a bone stock 3.42 geared 10 bolt. Autos are much easier on the rears

 

i also put down 393 JD, but in a completly different way

 

Unless you do stupid **** like dry pavement doughnuts.... A LOT.

My rearend grenaded under near stock power.