Got an issue with a Holley carb 4160 600 cfm that has caused me to set it aside.

Carb is running rich, to rich to be in garage with it running door wide open. I had rebuilt with a Quickfuel kit. After changing oil due to raw fuel being dumped in intake I found that it is leaking past metering block and running straight into intake. Bought Holley carb specific kit and viola....same scenario. I have rebuilt 10 or so of these in the past with no problems but.....

Specifics
FE 390 bored .030 mini dish pistons
heads measure 68 cc's
Comp Thumper (long duration)
vacuum only around 7"
power valve went from 5.5 to 2.5 both brand new and passed suction test
yes, brand new gasket seated properly in meter block

I even checked the original metering block and it had much larger holes than the 600 cfm should have so I thought I had it. Ordered a used 1850-2 which is same as carb and still same issue. Main body and throttle plate both have 1850-2 stamped on them. I ended up buying a brand new street Demon which is nice carb but scratching my head on the Holley.

 

Could be the main body isn't as flat as it needs to be or the fuel is getting around the power valve somehow. I had a demon the stumped me for a long time and it was the gasket around the PV, it had separated in the middle all the way around and didn't find it until it came off in two pieces finally, looked like 2 gaskets but it leaked thru that. I'd guess somethings either warped or cracked if that is where it is leaking..