lashed the valves on the 408 .003" tighter(.017-.019) than spec(.020-.022) and now i have a bog in low gear only and seems to go away as engine gets up to operating temp(180), but not completely. i have a prosystems 1000hp on it with 40 squirters. i tryed 35 squirters and its worse, 45's are about the same as the 40's, but feel kind of mushy.
i talked to patrick at prosystems and he told me to drill out the idle air bleeds til i could get the mixture screws in the 2 turns range. well i drilled them .017" to take them from .076 to .093, now the mixtures screws were at 1 1/8 and now are at 1 3/4 turns out. this has helped alot and now with 40's in it the problem is almost gone, but still has a quik stumble that i can not seem to get completely cured. any ideas what else i might try? i'm thinking the problem may not be in the carb at this point, but in the convertor. 727 with a 9.5" tight 4500 and 4.10 gear. patrick also mentioned tuning the power valve, but not sure which way to go with it. the slight hesitation is now from dead stop to about 25-30mph after that no problem and no problems in park either.