Looks like the guys have given some good info on this subject. Suggest you contact a reputable engine builder for recommendations. Typically, a street driven blower motor will perform much better with smaller carbs.. two 650 double pumpers set up for a blower should be close to what you are looking for. Remember, 10 to 12 lbs of boost with 8:1 slugs will require race fuel only...been there done that & 3 to 4 mpg @ $4.00/gallon isn't much fun. The cam you are running will also be a huge factor in carb selection. Im currently rebuilding the 55 for street use only (pump gas) ..the 502 with an 8-71 straight up & moderate blower cam should be very happy with a pair of prepped 750's.