'73 LeMans 350 Really rough start up Stalls if put in gear If I let it warm up for 4 to 5 mins, runs and idles great Are these indicators of a vacuum leak?

Probably not a vac leak or it would run rough all the time. I had one of these with a 2 bbl carb and it had a kick-up solenoid attached to the driver's side of the carb. It would kick up the idle RPMs when the engine was cold and then shut off after the engine reached operating temp. If this solenoid is not working, this would cause the symptom you are seeing.

Hmmm.... Thanks for the response brother. It's interesting because you're the second person to suggest the exact same remedy which makes perfect sense. Here's my problem. It's single bbl. & according to title & my research has 11,000 original miles on it. Perhaps there is the same solenoid only located off the carb. Wondering if single bbl. was standard & 2 bbl. was a common modification or option?

It was a standard item on these engines. It pushed against the throttle linkage on the side of the carb to keep the engine RPM's up during warm up. I put in a cut out switch in the dash so I could control when it actuated but some other owner may have just removed yours.

Thanks for the knowledge.Turns out its on the passenger side of the single barrel carb. Hooks into linkage on butterfly valve which was sticking just before full open. Hit all the linkages with some W-D & seems to have solved the problem, Now on to gaskets & water pump replacement. I use to enjoy this work......Thanks again for the help

You are welcome. Glad my memory of my car from 40+ years ago was a help! This was mine back in '73. Have fun with yours.