I imagine rich enough that you would see a puff of black smoke coming out of the tailpipe. But that's just a guess. It can't hurt to double check your ignition. Taking apart the distributor and lubing up the fly weights might not be a bad idea. Mine were getting sticky and causing all kinds of weird driveability issues. If your weights are stuck advanced when you set the timing, you'll actually be running way retarded. Disconnecting the the vacuum advance and watching your timing light as you rev the engine up slowly should give you an idea of whats going on. Any jerky, or lack of movement of the timing is reason to inspect. If it does not return to the same base timing, also inspect.
I know it's not the recommended setup, but I run a Carter P4070 fuel pump that I have mounted above the drivers wheel, where the emissions control was. It's been in service over 55k miles with no problems. I put it into a Holley regulator set to 3 psi. One of the things I like about this setup, is that the line from the tank up to the engine bay is all under vacuum, not pressure. Lines under vacuum spew much less gas if they fail. It also keeps the pump and wiring out of the road salt