I installed a new holley street avenger w/elect. choke to my newly rebuilt 350 , hooked up choke to 12v. ign.source. Once it warms up it won't run,just dies.I checked source no juice w/key off ,12+ w ign. on, 12+ w/car running what gives? I bought car w/ holley w/ no choke what am I doing wrong.

Assuming when it's warned up that the choke blade is open and your off the high idle cam (note: these are separate but related) ? If so, this has little to do with your choke setting but a lot to do with you low idle setting. Do you have your ignition timing, idle mixture and idle speed set correctly.

the choke blade is vertical when it dies, timing is @ 2 deg. b.t.d.c. as far as idle it was @ aprox. 600rpm in gear . I should also note that it ran fine until I cut about3 or 4 feet out of the power lead that came with the carb.

2 degrees of timing is not much at all, especially if you have any sort of performance cam. Try something like 6 degrees for starters. A little more ignition lead will make better use of the fuel and raise the idle speed.

I really don't think your power lead to the choke is the issue. I think the reason you car is running before you're warmed up is that the higher idle speed and greater fuel delivery is keeping the car running.