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Vacuum leak

Thats funny, I've never experienced a drop in fuel pressure from underhood Temps rising. As long as the fuel system is good there's no reason the fuel pressure would drop.

To add to what's been said, I'd drop the fuel pressure down to 6 lbs.

I know when you go up in pvcr size, the afrs at wot should be 12.5-13.0. As far as figuring pvcr size to jetting I can't answer that.

Fuel pump should be ran through a relay then to a 12v key on power source at the fuse box. To the alternator wouldn't be recommended.

Update on my stumble. Took it out today, and with the carburetor back to where it was when I got it it runs alot better. The stumble is still there, but it only stumbles less than 2 seconds and it goes like a bat out of hell. Cruise afr's are low 11's so I need to drop the PVRCs a little. But...

I was always under the impression you wanted the supply line bigger than the return line. But I see I'm wrong

The return line can't be the same size as the supply line.

Never heard of anyone paint a carburetor

When you run a deadhead system, it makes the pump work that much harder which in turn would shorten its life.

I prefer a return style regulator as it will keep the pump cooler, and make it last longer.

The way holley or pro system says to check vacuum at idle is wrong. The Best way is to see how much vacuum you have at cruise and devide it in half and add 2 inches. Which you would run either a 9.5 pv or a 10.5. And that will make it open sooner. Then tune for your power valve jets for wot.

If it's a blp carburetor that's been modified by Dominic thumper I'd give him a call. I have the same card with all the information on it like you do, that's why I'm thinking you have a thumper/ blp carburetor.

All I put on the threads is assembly lube.

I was told to back the idle screw so the throttle blades are completely closed. Then turn them clockwise 3/4 of a turn and you should be set.

I have a 950 thumper modified carburetor. In order to get it happy, the jets had to be dropped about 4 sizes front and rear. Make sure your idle air bleeds are 73. And the high speed air bleeds 28. At cruise my afr's are 12.7 13.2. But the exhaust is clean and plugs have never looked better.

Try some Gibbs Lubricant oil.

Holley black pump with a aeromotive return style regulator

Well when I put the return regulator on. It actually made the pump sound better. And fuel pressure was more consistent. And it's been proven.

I ran a dead head system for many years. But when I upgraded the fuel system I decided to get a return style regulator. I'm glad I did, it puts less strain on the pump which will keep it cooler and extend the life of the pump.