The biggest needle seat is too small, so you use a Gross jet. Two balls  instead of a needle. Then you find the hole into the needle and seat well is  limiting the flow, so you drill that out. Then the bug screen in line with the  needle flows only half of what you need, so you throw that out. Then it runs OK  but still goes lean at the top. So, you raise the float level until the boosters  drip, then lower it just a bit. Then increase the fuel pressure until the needle  and seat cannot control it. Then lower it just a bit. Then you drill into the void that would have been the accelerator pump well  for the other handed version of the same carb, to increase bowl volume. Then for short tracks all is well, and for long straights you can rig a  backup pump to come on when 5th is selected.  Then you can use a Weber carb at twice its rated flow.
 
Piece of cake.
 
Lynn E. Hanover