Dual 390 cfm Holley 8007's (vac secondary, similar architecture to the 4160) on a tunnel-rammed 5.0L H.O. 302. Carbs have been completely rebuilt. Car runs great, but for reasons I do not understand, the floats stick at the strangest times. I drove the car on Saturday -- it had been garaged for a month. It fired right up, idled great, ran well. I drove it all day. Garaged it, went out tonight, and started it. It started with a touch of the key, idled great, I let it warm up while I took the T-tops off, and after about a minute of idling, it started running rough, died, and I smelled gas.

I took the scoop off and fired it up again, and saw that the rear carb was leaking gas out the lock screw / fuel level adjusting nut assembly for the secondary metering block (8007's have metering blocks for the secondaries, but there's an adjusting screw identical to the primary bowl) and was pumping gas out of the secondary bowl vent. I loosened up the screw and fuel level adjusting nut, retightened it, and that solved it, temporarily -- I started it again, it ran for another 10-15 seconds, and started coughing again, this time spitting gas out of the adjusting screw and bowl vent for the primary metering block of the same carb.

It was doing this last winter, too. I tore the carbs completely down at that time, both of them, replaced the gaskets and reset the floats, and it ran great. Now, it's doing it again. I am one busted knuckle away from chucking them both and replacing them both with Edelbrock 1403's, but the glory of running dual Holleys is just too sweet to give up. As yet.

Any ideas what's causing this? The last time (I haven't taken it apart this time, yet), I just backed the fuel level nut / locking screw assembly out and back in, and that solved the problem; this seemed to do it for the secondary metering block this time, too, but I was in a hurry and couldn't screw with it any further. One time before -- last winter -- the float seemed to be actually jammed; I took the bowl off and the float worked fine after I took the fuel level nut/locking screw assembly all the way out and shook it around. This has happened on both carbs but it seems to happen more on this one.

Any ideas?