help with engine issue

[72 grande]

Hi I just finished replacing the head gaskets on my car. I did a tune up during the process. I went to start the car up and it was at a high idle I tried to adjust the carburetor and nothing. After the car is running for a bit the idle will fluctuate from high to so low it almost stalls. Anyone have an idea what it could be I was hoping to drive the car to Syracuse nationals tomorrow so please help

 

[Mike65]

Check to make sure you do not have a vacuum leak. Unhook all the vacuum lines & cap off all the ports & see how it runs. You could also spray some carb cleaner around the base of the carb at the manifold while it is running & see if it smooth's out.

 

[71mach1]

Do what Mike65 said to do. I had gotten an Autolite/Motorcraft 4300 carb for my 71 Mach1 (351 4V). Either the top plate or the bottom plate was slightly warped and was causing a vacuum leak. (Wound up getting a new Holley!).