If you get those carbs in tune, It will run fine, even on a stockish 318, A single carb set-up or smallers "carbs" of coarse would run better, but you won't have the "WOW" factor which i'm sure thats what your after & you already have the 600s, You may also need to jet those carbs down a bit.
The 1st. thing i would do is make sure the ignition is strong & in good shape, & get a quick timing curve in it with as much initual timing as possible, a good adj. dist. helps wonders with setting up the curve & RPM your after for total timing, I like the MSD 8534 Billet. Its simple, then run a digital box or a Mallory Highfire 6853M 6AL.
http://www.jegs.com/i/MSD+Ignition/121/8534/10002/-1http://www.jegs.com/i/Mallory/650/6853M/10002/-1
