I have a Holley 390 on my 240 via an Offenhouser DP6019 (Dual Plane) intake. After putting a refresh kit in the carb I have resolved a handful of issues I was having. I bought it "Refurbished" but found the secondary float was cracked, the power valve was malfunctioning, and the secondary spring was way too stiff.

My chronic issue is that when I shut it off a fuel smell emanates from the doghouse and all of the fuel drains out of the fuel filter, I'm guessing back towards the pump but thought there was a check valve in there to prevent that. If it sits for more than 10 minutes I need to crank it over a bit for it to deliver fuel again. I usually end up pumping the accelerator about 4 times to prime it. The funny thing is if the van sits for a few weeks this symptom goes away for the first couple of drives.

All fuel lines are new including the pump and there are no leaks that I can see. I measured the fuel pressure and it is within range for the Holley (5-7 PSI).

Is the carb getting too hot and fuel is boiling out? I don't have a spacer on it right now but I have a 1/2" phenolic I can put on. Any thoughts?