421 banshee stock carbs jetting

[Wes2003 banshee]

I just built a 4 mill serval 421 banshee and I’m trying to run stock carbs for just a little tell I can get bigger ones. I need to know what jets I should be running. I have gold series pipes  with t5 silencers, stock reeds, +4 timing advance, pro design cool head with 20cc domes, running 110 race gas. I’m at sea level at Winchester bay, OR.

Edited July 2, 2022 by Wes2003 banshee

[JayB1rd]

Curious if you have had any luck? I’ve got a Serval 421 in the works, going to run it on pump gas with T5’s and stock carbs for the rest of the season at least. My old 66mm bore stocker seemed to like 320 mains with 2-3 degrees advanced timing.