Maybe you can get moved to the 385 forums.

460s of that era were about 230hp, 390tq. + your mods, - age and wear, you are somewhere near that. Change the timing set, maybe 15 or 20 hp...WAG.

Pre-71 methinks for the timing set, but you can search the 385 threads or, if you post gets moved there, get an answer. Monsterbaby is an excellent resource for these engines.