that is why i said plug it.. small 2.5 may work but i have plug them and go up on the jets . no i would not drill holes in the butterfly .just open the back barrels up there is a small set screw on the end of the rear shaft to open them up and yes i am taking about tube nozzles you may not have to use bigger nozzles but go down on size if you run the tube type. on the MSD i think you could go two the sliver bushing? one size bigger up from the red will let you run more on the crank