lol ok, I will go do that now and will update in a few mins, thanks for the clarification.

Sorry :o

Yes, I meant mixture screws, not the throttle stop or fast idle cam screw.

The thought is that you are probably getting too much fuel and by screwing the idle mix screws in we can prove that. If it runs with the screws all the way in we know there is another source of fuel.

OK

I started the truck with the cloth in the secondary's, started just fine, turned drivers side mixture screw in to seat and engine slowed but did not die, turned the passenger side mixture screw in and engine died right about the same time the screw set in seat, this is all while the cloth is in the secondary barrels.

Yup, it is getting fuel elsewhere. Power valve maybe. Accelerator pump possibly. Good call Jim.

Okay, that's a good sign.
Have you removed the sight plugs from your float bowls?

So, what's your suggestion? Tear the Holley down? (Or install an Eddy? }>)

yes, the sight holes I removed on both ends of the carb, the one in the back I had to shake the truck pretty hard to get the fuel to flow from sight hole, the hole in the front (primary) the fuel is just a hair below the sight hole.

Gary, I don't have any problems with my 0-80457s ;)

I'm trying to understand what happened "all of the sudden" to his carb, and why going through it didn't resolve the problem.

If he has a sunk float it will be spilling over through the boosters.
But would be apparent at the sight plug.
These carbs do not have externally adjustable float valves.

Jim - I'm gonna lurk on this as too many cooks spoils the ...... carb. Keep on keeping on....

I'm kind of lost here too.
6 pages and no answers...

If it were me I would set everything to baseline and smoke test for vacuum leaks.

The only thing that makes sense is the truck stumbling and then picking up again.
MAYBE it is too lean and the lack of vacuum is allowing the PV to open below 6.5Hg

I didn't open up the carb and go through it

mine has the needle valve on top of the bowls but I am guessing they are set right as the fuel is about at level.

Is it possible that I installed the power valve to tight? or the pump out of wack? I know that when I installed the carb after rebuild the pump under the primary bowl wouldn't set right unless I turned the nut most of the way out, then set the arm, then tightened the nut back down

is it possible I didn't get the arm right? maybe pushing into the pump when it shouldn't be?

6 pages - no problem for me. ;)

Has the engine backfired since you put the new power valve in? If so the PV may be blown. And if you didn't put the check ball/weight in on the accelerator pump it can pull fuel via that passage.

IIRC there should be a .015 gap setting when the bowl is in place.

It should definitely not be making contact.
How about the other end?
Where is it setting on the colored plastic cam?

Gary,
Holley's after 1992 have a backfire check valve installed from the factory.

This was an issue with 4180's but not this carb.
I thought perhaps he had the wrong gasket behind the PV, but if it dies with the idle mixture screws in, then I don't think the PV is at fault.