If you have good compression, and have rebuilt the carb, then you have 2 of the 3 "ingrediants". How about the ignition? Vacuum advance (if it has one) working? Distributor plates stuck? Coil and condensor matched for impedence? Wires and plugs correct (not both resistive)? Timing where it should be? Also, correct thermostat installed and working? That engine should run great on 87 octane.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop