Vacume Spring??

heres something that may help change the shooter on the main side to a #31 with the extention tubes it will get the fuel to the venturies quicker i like a 68 to 70 jet on the main side you will just have to experiment read the plugs etc. till you get the right size figured out .also how much vaccumn do you have at idle? you need to know this so you know which power valve to use. you may have the wrong one and the enrichment circuit will not work if it is too small. most holleys come with a 6.5 power valve which is a good starting point but you can tune from there to suit the engine based on the amount of vaccumn.