No top end power, need help

So I've recently noticed that I am really lacking in the top end power. When I open up the throttle the last 1/4 has no power gain, and if I let off the throttle a bit I have more power. Im thinking it might be timming? I am currently running at 10 degrees BTDC. The book says I whould be at 5 (I think) but it does not run well at 5. It also is a bit rough at idle, and I have tweaked with the idle mix screws and cant get it to run super smooth. It doesnt die at idle, but does run rough and once it hits a little higher RPM it smooths out nicely.

Specs:
66 dodge dart 273 automatic
Edelbrock 4 bbl (600cfm I think?)
3.22 rear end gear
6a MSD box
Mallory distributor with new spark plug wires (solid core)
Runs on the cool side, but my guage may be off.
Uses a ton of gas, but that is expected with a 66 (around 13 mpg but my odometer doesnt work so I cant easily check the mpg.
I think it was originally a slat 6 but had the 273 when I bought a few year back.