If you are going to stay with the tunnel ram, you need to either turn the carbs sideways and run a couple of Holley knock off 650 double pumper carbs. A tunnel ram and small carbs are just worthless. The math is wrong on carb sizing. So don't bother with that.

You need a carb that is easily tuned. That's why the Pro Form 650 is a good buy. You can change everything by simply changing some brass.

If you don't want to turn the carbs sideways, then a couple of Carter/Edelbrock 600's will work.

If you are not willing to learn to tune a carb and do the work, skip the tunnel ram.

Also, no one asked what you have for a cam. Tunnel ram stuff is uber sensitive to cam timing. Most guys over cam the hell out of them, and then complain they have no bottom end. If you don't know what the cam is, or the cam wasn't chosen with the tunnel ram in mind, you either need to chant cams or lose the tunnel ram.