I would have replied earlier but it was time for my nap! You guys should be glad to learn that you are not old, you are in your prime! It is not going to get any better after 50. Here is a set of dyno curves from Comp cams if the original guy who started this thread is still listening.

http://www.compcams.com/Technical/DynoSheets/

These curves show the cross over of Torque and HP at 5252 rpm nicely and they all seem to be for a standardized overbored 350. I don't see a 383 in the list. That said, I note that even with a roller cam and long duration,the 350 displacement does not reach the 450 HP mark so as Eric says the build up should be based on a 383.

Don Shillady
Retired Scientist/teen rodder