Rebuilt engine runs strong cold but sputters when up to temp

Vacuum diagrams are impossible for me to find as well as carburetor specifics. Ignition system diagnosis cannot be found just like most parts I've had a hard time tracking down. Fuel cut solenoid works fine. Not sure about choke and fast idle operation as well as thermostatic choke control specs. Have been through the unhelpful Chilton manual and am on my knees begging for a diagnostic procedure. My 1978 1/2 ton 2wd pickup with 2bbl downdraft carb assembled in march 1978 is so close to factory running order aside from the sputter and die out at operating temp. Fuel mixture adjustment procedure would help as well as anything else that may cause this problem. Emission controls are to federal specs. Possibly ignition issue since timing light sputters when engine does. Electronic ignition. Any help greatly appreciated. Distributor does not seat flush with head. Am I missing a spacer bracket or is my head worn?