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

Carb is too small and it starts leaning out right before the HP peak RPM. Throw a 750 cfm carb on there (Holley for max HP IMO), get the A/F dialed in and it should pick up 30-50 horses. You might be able to put in a couple more degrees of timing advance as well.

Also how long ago was it tuned up? Cap, rotor, plugs, check plug wires etc... what kind of "flat-top pistons" you said you bought the parts do you happen to remember or have a receipt? And how tall are they (zero-deck or below-deck)? What about duration specs on the cam? Sorry for all the questions but all these things come into play.

EDIT: nvm about the cam I looked up the specs but the E3N cam says it only has .440/.465" lift with 1.5 rockers and 215/225* duration at .050" lift... rated for 1500-6000 RPM yeah I think your carb is much too small. I run the same 625 AFB on mine for the street but I know for sure it's choking down the power above 4000 RPM, and my cam is about 1 step smaller than yours in duration but with more lift and 1.6 rockers (Lunati Voodoo 256/262), also mine has true 10.5:1 comp.