i have a 700 dbl pumper,a pro form main body & would like to buy holley's hp metering blocks but can't find them at summit or jegs .who else ,i don't really like the purple ones . carb is going on a eddy headed 408 ,250 dur. 1 7/8 headered 4-speed dart anybody have an idea where i should start out with jets and should i stay with 30cc or go to 50cc shooter .this is a fresh build .