Need help with engine problem

[drdave69]

My ZZ502 is still not running very well after a few attempts to fix it. I drained the fuel and had the carb rebuilt (by Eric, thanks) and installed new: plugs, plug wires, distributor cap/rotor and new coil (HEI). The engine still doesn't want to start and run very well. It will NOT idle below 1000 rpms. I checked the timing and it appears to be correct since there is only a single indicator line on the timing marker and it was on it at 1000 rpms. I checked the intake and carb with starting fluid to see if there is a vacuum leak and did not notice any increase in rpm.

Is there something else I can look at? Could the timing chain be stretched? Is there a valve train issue?