New carb advice

[84_GT350]

Ok...I'm sick of my carb. It's running way too rich and I've spent way too much money chasing this problem (I think it's a sinking float but nobody can varify that). ANYWAY...I'm gonna get a new carb. I just can't decide on a size. I could get a direct replacement for the one I have (Carter 625cfm) but I always wondered if that was too big and bogging the motor. I mean, it's not a whole lot more built than a stock motor. Should I go with a 600cfm Holley or stick with the 625cfm rating and get a Road Demon or something?

------------------
1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s