Wants to stall when you take your foot off the accelerator?

It sounds like you have a vacuum leak like a PCV hose that has a crack in it. Please use this guide when the engine is cold only:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

And this guide may help as well:

https://www.2carpros.com/articles/stall-at-idle

Did you try increasing the idle speed on the carb? Let us know what happens and please upload pictures or videos of the problem so we can see what's going on.

So, it seems like a fuel issue. I noticed the gas filter was packed sold full of fuel, normally it runs about 1/2 full or so, but never packed full. Seems like it was flooding out, only responding to full throttle during stall. I started it and moved the gas regulator to a position that did not fill the gas filter and the test drive went fine, but I'm not entirely sold on this fix, so we'll have to see how it goes. Recent carburetor rebuild due to a small hole in the float, so it was dumping fuel in the carburetor flooding it out. These symptoms are very similar so much so, that I first thought it was the carb and if I had another one, I would have put it on to try and fix it but the symptoms were a little different and the rebuilder is the best in the valley so carb should be good. I have checked for vacuum everything looks good with the hoses, I could get a can of carburetor cleaner to look for vacuum leeks. So, what do you think?

packed solid not packed sold.

Yes, that is what I would do, use this guide when the engine is cold only:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please go over this guide and get back to us.

Have not found vacuum leak of any sort, it runs very well most of the time and then it will just RPM stops but responds to flooring it that brings rpms back up, turn the truck off and it usually resets and runs good again. Last time I tried something I took it on two test drives over five miles with several heat cycles drove great, like a new car, so then I get in it today and it after driving through a heat cycle starts acting up again. If it was vacuum, would it not be constant all the time? 1966 so no check engine light or any of that other new stuff. About 500 miles on motor. Since it only happens every once in a while it's hard to tell, I'm still confused, it had bad gas in it when it was started maybe the gas filter should be changed since it's been in there from the beginning. I have a Edelbrock electric fuel pump, a gas regulator and that's it from the gas tank to the Edelbrock 750 carb. It really seems like a gas problem as in getting to much flooding it out. I say that because when I floor it, it always recovers. So do you still want me to search for vacuum leeks? Would a vacuum leek have that kind of symptom? Only thing I haven't tried to spray carb cleaner at yet.

Vacuum leaks can affect the engine runabilty at different times and conditions, it would be nice to rule it out, also does this engine have an EGR valve?

1966=no you should know that they were introduced around 1972.

I didn't know if it had a newer engine in it.