440-6 w/10.5 comp. & moderate cam & about 10-11" vacuum. My six pack has been running pig-rich (can smell the fuel out of the exhaust) & I have been "de-tuning" the carburetors back closer to stock. The only non-stock carb parts I have now are a 3.5 power valve, the power valve holes in the metering block drilled, a Promax back carb baseplate, unplugged the front carb idle mixture screws, 3/32" holes in all the outboard throttle blades (center carb blades no holes). The power valve is brand new and I haven't had a single backfire. I'm running #64 jets & un-modified outer carb metering plates. I can get the engine to idle down to about 700-800 rpm, but my vacuum is around 5" when it's that low. I've been trying to set the idle fuel mixture on all 3 carbs & using the "block the outer air bleed hole" method on the outboards. I started with the outboards 1/2 turn out & the center carb 1-1/2 turns out. The only real effect I got was when I closed off the rear carb (zero turns out) which made the idle go up. It "seems" moderately better with the center carb at 1 turn out both sides. The problem is I "expected" to need the outboard carbs opened up at least a little bit and when I plug any of the outboard carburetors' outer-most air bleed holes the idle doesn't change. From what I found online that seems like the mixture is correct on the outboards.... but something doesn't seem right.... and I can still smell a little bit of richness in the exhaust and the tailpipes are a little sooty (outboards closed off & center carb 1 turn out each side). Any ideas?