340 - This thing should run better

Just installed a budget rebuilt 72 340 in my 67 dart. First time ever rebuilding an engine. It sounds great and runs pretty smooth, but it does not have the grunt I was expecting. Please help me tweak it. Here are the details of the rebuild -

.030 over 72 block with stock "J" heads 1.88/1.60 (did not do a valve job, just cleaned everything up).

New pistons and rings - silvolite 10.2:1 compression, but since they're being used with the lower compression 72 heads, I'm only getting about 9.4:1

Cam is 280/480, 110 deg (I think)

Cast iron manifolds with 2 1/2" exhaust and flowmasters

Edelbrock RPM Air Gap and 600 cfm Edelbrock carb

Still running points distributor, about 12 degrees advanced.

It's connected to a 904 with a shift kit and the torque converter only stalls at about 2300 RPM. 8 3/4 rearend with 3.91 sure grip.

This engine should be somewhat of a screamer, correct? I'm dissapointed with it's performance. Help!