Supercharged carb modification

[Mike Golden]

Has anyone drilled 4 small holes (1 in each carb butterfly)on a holly 390cfm 4bbl to smooth out the idle on a magnacharger setup? If so what size holes? Thank u.

 

[one2dmax]

My experience is that the 2 barrel works superior to the 4 barrel on these units. Here's info on that unit from another supercharged bike guy (and i have the pleasure of riding with one of these)
Holley 4412 with a 30cc accelerator pump, 130 needle seat, boost reference the power valve. Take the choke off..I always milled it flat. Works way better,cheaper and smoother than the 390 crap.

Now, having said that I put a dowdraft webber on one which worked out quite well. That was a high boost build and would pull the front wheel up at 100mph in a roll on. Crazy power with it.

 

[Mike Golden]

My experience is that the 2 barrel works superior to the 4 barrel on these units. Here's info on that unit from another supercharged bike guy (and i have the pleasure of riding with one of these)
Holley 4412 with a 30cc accelerator pump, 130 needle seat, boost reference the power valve. Take the choke off..I always milled it flat. Works way better,cheaper and smoother than the 390 crap.

Now, having said that I put a dowdraft webber on one which worked out quite well. That was a high boost build and would pull the front wheel up at 100mph in a roll on. Crazy power with it.

Do u think boost reference the power valve help the 390.trying to smooth the bottom end out a tad.trying to avoid a new carb but might have to bite the bullet and do it...just use a 4bbl holly to a 2bbl holly adapter I'm guessing...hopefully hole in tank lines up when done! Thank u