Edelbrock part throttle surge help

Have a 1405 (600 cfm) on my nearly stock 318 (340 cam and performer intake, 4 speed, 2.9 gear ratio rear. I also welded the dizzy mechanical adv so that i can limit the mech advance and get a little more initial (per posts here on FABO). My total is set to about 32 (i can't remember when initial is but i think i have about 18 mech advance, so ~ 14 initial)

I've completely rebuilt the carb (all stock tuning) and i can get it to idle fine and high power mode seems ok when i step into it. The problem i have is that there is a nasty part throttle (cruise) surge that i'm trying to eliminate. I've richened the mixture to no avail. I also plugged the vacuum advance to see if that was my problem and that didn't help either....

I've read the eddy tuning guide and it sounds like my problem is that i need to bump up the rod to richen the mixture in cruise mode. Part of me doubts that my engine combo would require me to increase the mixture over stock.

Any help would be very appreciated!