yeah both the 350 and 330 seem too rich
with my mods i have a 320 in, they didnt have a 310, seems sluggish on the bottom but just ok on top, the cfm airbox didnt seem to make any difference when i added it, ran the same,
but it pulled very very hard with the 290 in, but 1 pass on the wot run wasnt givin me much plug color
i was just going with what the toomey kit uses low 300's ?????,
and figured better rich than lean, plugs really dark and wet, but will not foul, anyone think the 290 is too lean???
may try the 35 pilot i got and put the 290 back in, or get on some "glue" and maybe figure this out???