Dyno'ed My 360..it's a pig..what next?

You pretty much have stated the obvious,the 576 castings though a replacement head did come with more material in them and were meant for superstockers to work over and flow less than other big port Mopar heads,even the 308s they replaced.
The carb is costing you 20+ HP and what cam are you running?
If your compression is really low even some ported big valve 302 heads,with 1.88" intake valve would boost performance a lot.
Especially seat of the pants torque.