Check the fuel pump output- - - -it needs to be at least one pint in 30 seconds at idle speed. Also, run the same RPM in several gears to see if the miss/surge is related to engine RPM or vehicle speed (not likely). Id the HEI a stock type or some sort of aftermarket system?
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!