Big Block Edelbrock limitations.

Well, since you guys are asking, The current combo is a.030 440, 1973 block. Cast crank setup, TRW 9 to1 pistons. I know the compression is lower. Cam is a Hughes flat tappet hydraulic with .504 intake, .515 ex. Duration is 272/276* . Heads are Eddy RPMS, 84 cc. with .030 shaved off the block side. Intake was milled too, but I forgot what the formula was, but I can run any intake. Carb is a 750 cfm Race Demon. The converter is an ATI. It doesn't stall like I think it should. Starts pushing the front tires at 1200rpm. Supposed to be a 3k converter. 727 TF full manual VB. Rear is a locker with 3.91 gears. Shifted at 5500 rpm. Ran a best of 12.12 @110mph I believe the 60 foot was 1.76. On pump gas. I think it's at the limit of it's performance, and would like to of course make it perform better. Deep in the 11's would be nice, but I don't want to empty my wallet to accomplish it. That's why asking how much the RPM products can "support". Thanks!