On my 69 318 i have an eddy performer along with a holley 650 and a oversized 509 car (came that way). When the car is cold it runs and idles pretty good. however when it gets warm it runs terrible and hardly wants to idle in gear. I also have noticed when adjusting the mixture screws the idle increases as i turn them in when normally the engine should die. Compression test has shown alright compression across the board , while not great its all close together. 115-120 on all 8 cylinders. I have checked for vacuum leaks anywhere and everywhere they could be and have none. Before i go swapping the cam I'm beginning to think that i could have a cracked intake manifold. Anyone have any methods of checking it without removing it? I am going to swap the cam to something more suitable and if the intake is trash i would like to do it all at the same time. Also, for what its worth i could never get any fuel volume worth a darn until i installed an electric pump, as if the eccentric on the cam was rounded off or something of that nature. I have installed new MP rockers and pushrods also since i had them laying around. Didn't do much to help. Any advice would be appreciated.

Have you tuned the ignition and carb? That .509 is going to have zero vacuum. I'd bet the power valve is open at idle messing everything else up except when it's cold and needs the fuel.

Mopar you can spray some carb cleaner around that intake,that will let you know if there is a leak,hence the idle will go up.

Which Holley do you have? Reply with the list number stamped on the drivers side front of the choke air horn.

It's usually a 4 digit number with a dash and another digit after that. Example, 4777-2
Then under that is another set of numbers, those are the manufacture date.

The 509 with its 240+ degrees of duration is much too large. On a mild 318 I'd be looking for a camshaft with a maximum of 214 degrees intake duration at 50 lift, and would try get right close to 210.

Engine speeding up as you turn in the mixture screws is the classic sign of power valve problems. I think moper has the right idea. Pull the front fuel bowl and the metering block. Replace power valve with a 4.5. It'll help either of two ways:
1. Replacing a leaky PV diaphragm with a new one, or
2. Keeping the power valve closed at idle.

R.

The carb is a 650 double pumper from the 90s. It's old but ran great on the other car. Also I have timed it as best I can without a dial back light, also the power valve is brand new and a 3.5". I get around 7-7.5" of vacuum at idle. I know the cam is completely absurd, I dunno why the guy I got the motor from put it in. I've also tried a brand new eddy 600 on the car and have the same problems fwiw

First order of business would be to replace that cam...

Fully agree. Just want to make sure I don't end up chasing my tail. I want to to everything once lol