1967 Ford Mustang Miisses severly when warm

Any other changes? IE- distributor is it is electronic or points? If electronic who's distributor is in it? Which heads did you get? Did you do a cam too? What head gaskets and intake manifold did you use? The more info you can give the better I can help.

Heads are Edelbrock performer 6000 series, electronic points & coil from MSD were installed prior to installing the heads and the engine was running fine then. Manifold also from Edelbrock as is the 750 cfm carb with manual choke. Engine is 390 which was re-built about 15,000 miles ago. Gaskets were a package from Mustangs Unlimited, unknown manufacturer. Car starts very easily with full choke when cold. When warm the engine starts immediately with no gas. Engine runs very well when cold, lot of power & torque under load. When operating temperature is reached driving at 30 or 40 mph the missing is first noticed. Gets progressively worse until the car can only be driven with the engine at idle speed. Currently planning to replace the MSD points & coil which were installed about 4 years ago.

Ok sounds good to me. I would check the coil and the electonics in the distributor too. Have you checked to see if it is running lean once it warms up? Once warmed just simply start to slowly choke the carb to see if it starts to run better. Let me know what you fnd. Also what did you torque the heads and intake too?