I just put a 477 lift comp xtreme energy cam in. I had the carb rebuilt, it's a 600 cfm holley. I turned the idle up, so it would stay running at an idle, but it goes into gear a little hard, it doesn't clank or anything, but it lets you it's in gear. It has the 727 torque flight automatic. When i put it in gear, it wants to idle down to low. I have to keep my foot on gas. I have a 4.5 power valve, i don't know how to tell if, the power valve is opening at idle. I checked the timing by ear and it's happy where it's at. This is my first high performance build, it also has a 5 psi electric fuel pump, it was the only electric pump the shop had left, so i bought it, it used to have a 10 or 12 psi pump. I have ignitor electronic ignition, i have a high rise weiand intake. The motor still has the 2 barrel heads. I don't have a clue why it won't stay running on its own, when in gear. 2 wks after i put the cam in, i moved a full size trailor house, i barely touched the gas, just enough to keep it at an idle. The truck is a tank, i just want it to run correctly, right now it's a pain in the *** to drive. It's been sitting for about 6 months, i start it once a wk, to stop the gaskets from dry rotting, everything is brand new.

 

It also has the original 1974 360, it's all rebuilt brand new. I think the problem is the carb, but i only know so much, i have never encountered this problem before, so i don't know how to fix it, nor do i have the money to take the truck to a shop, everyone i know is to lazy to help me. The truck was my father's truck, i love it, it's all i have left of my father besides, good memories, it was cancer, that took him. The truck means so much and it's so powerful, please help, so i can drive it again. I plan on one day completely restoring the truck.

 

Sorry for your loss.
The heads shouldn't be a problem. They weren't for me on my '77. Then too, I didn't change the cam.

You need to start with verifying you have no vacuum leaks. After that you'll need a vacuum gauge and one of those "lazy" persons to help you by using a heavy foot on the brake while the truck is in gear.

Holley has videos on how to install and tune. It's well worth the time to go through them and learn how to work with these.

https://www.holley.com/blog/carburet..._and_tuning/1/

 

I assume it's a fairly lopey cam so you will need to raise the idle. More details on the components would help. You may want to get a higher stall speed converter since it seems your set up is for upper rpm power.