Update...Definitely rich, I guess my eyes were watering too much to see the black smoke before. Removed the carb, took it apart, installed a 4.5 power valve, new gaskets. The 6.5 valve that was in it was still good. The carb is basically new and I didn't find any evidence of any drilling or any other mods. I noticed the primary and secondary transfer slots were fully exposed but was the only way to get it to idle. I adjusted the throttle plates so the transfer slots were right, drilled a 3/32 hole in all 4 throttle plates and stuck it back on. Runs a lot leaner than before but not close to good. Still little response from the mixture screws. They're sitting at 3/4 turn now. I'm at a loss! I guess I will keep drilling to get more air as it seemed to be in the right direction.  Thanks!!

Drew, been sitting for four days and no obvious leaks, fuel wise. I'll take it apart to see if anything looks wrong. Like I said, runs good, idles good, just gassy at idle, way more than acceptable in my opinion.

Subject...the other big block, 460, Holley Brawler 750 carb, floats correct. At 750, 800 rpm idle, engine runs good but super rich. Pump gas deal, don't know the specs of the cam but fairly lopey, 8 inches vacuum at idle. The ported vacuum at idle was manifold vacuum, obviously drawing fuel from the mains. I opened the secondaries  to back off the primaries enough to zero out the ported. Still stinks up the place. The mixture screws have little to no effect. Power valve is 6.5. I was thinking of going to 4.5 but I understand it has no effect at idle. Jets are 72 primary, 82 secondary. Any help will be appreciated!

Installing cam bearings. New front bearing has a notch perpendicular to the bearing, from one hole to the outer edge. Inward or toward cam thrust? In case anyone's interested, 74 block, original bearings, 2 thru 5 oil holes at 2 o'clock or 8 with the block upside down.

MeanGene, I might take you up on one of those carbs. It's still stuck. Pretty sure it's the plates rusted in the holes as there was evidence of mice. I'm going to try the CRC next. If that doesn't work, maybe some weak acid. Patience is wearing thin and if there's a bunch of corrosion in the bores, carb might be junk anyway.

I have this 4100 carb. This thing is complete and untouched. I want to use it on period correct 66 Fairlane GT S code. The only issue is the secondaries are stuck. Been soaking in Kroil for a week but no go. Any thoughts on this?  It's a really nice carb and I don't want to screw it up.  Thanks!

Ross, pin height and crowns are the same on all 8. It is a temp motor till we can come with something more exotic. I'll try to talk the owner into cutting the deck. Duck...Yeah,there is a slight difference in that area. 360 pistons AND rods on a 390 crank?

Thanks!!