Trouble getting my barracuda running

[Matt13]

So, I just put on my brand new Holley 600cfm carb. All new wires and plugs. New ballast and ECU. Battery fully charged. Fresh gas, new fuel filter.  All this and she still gives me hell running. I'll pump the gas twice and she'll fire up immediately, then die right away. I'll go though the process of her starting/dying about 10X until I can get to the carb and finally coax her into staying running. Couple of backfires through the new carb and a few out the exhaust. After about 10 minutes of running she'll stay running but idle kind of fast. Even warm, I can't get her to kick down into a lower idle. Timing?

[Chryco Psycho]

No more likely carb , if the choke is not fully engaging it may be difficult to keep running when cold , also the float level could be low
If it has high idle when warm it could be a vacuum leak at the base or one of the ports on the carb or there is a separate fast idle screw on the passenger side of the carb or again the choke could be sticking keeping the fast idle cam engaged .

[Matt13]

It's a mechanical choke so I have her fully opened to start cold. Don't know why she starts immediately then dies right away. I checked for leaks and found none. Also, all vacuum lines are new.

[Cuda Cody]

What cam, compression and timing are you running? Fresh build?

[Matt13]

What cam, compression and timing are you running? Fresh build?

No idea on any of those. 1971 318 w/1991 swirl port heads. Got the car about 3 months ago and she was barely running. Heads look like they have been rebuilt, but not sure about the engine. Sounds strong when running, it just take a lot of work to get her to the point where she stays running.

[headejm]

Sounds simple but...do you have the spark plugs routed to the correct cylinders? Exhaust backfire tells me something is wrong with the ignition, valve timing/adjustment, or burnt valve maybe? Bad distributor cap? 

[Solarguy]

It's a mechanical choke so I have her fully opened to start cold.

choke should be fully closed for cold start and opened gradually as engine warms

[kathyscuda]

since you don't know anything about its past.
pull the cap. turn it over with a ratchet to your marks TDC.
were is the rotor pointing.
#1 hopefully.
check your wires again. ( firing order)
did you put a timing light on it.

[Chryco Psycho]

it starts easily because you pump it , once running it immediately goes lean from lack of fuel with the choke off , the backfire is normal if it is lean .
If the idle is too high when warm there is a fast idle adjustment on the passenger side of the carb that may need adjustment .
I agree it may run better with more advance but that is not the cause of the stalling when cold

[Cuda Cody]

If it was me, I would start at the beginning.  A basic compression check would be first on my list.  Then I would set Top Dead Center and set the timing.  Then work down the list to double check everything.

[RUNCHARGER]

Agreed: You've proven it actually runs. Compression check, measure timing chain stretch, check TDC, check timing then tweak the carb.

[Matt13]

Excellent. Thanks for all the advice guys. I've got some work to do!

[headejm]

Too bad I don't live near you. Sounds like fun. 

[Cuda Cody]

If you can't get it solved, you could fly @Chryco Psycho  in to your place (after the virus is gone) and he will get that thing running like a top.

[Matt13]

Too bad I don't live near you. Sounds like fun. 

Actually from Illinois (Oak Lawn on the SW side)