How much oil should my Six be leaking?

It shouldn't leak any oil or trannie fluid at all. BUT I can tell you my dart leaked tranny fluid like crazy untill the transmission service was done. The transmission fluid pan was leaking at the gasket. Check the gasket.

If you do your own work, jack up the car and look for the fluid smeared down the bottom of the car. Of course, this only works if the car has been driven a decent bit with the leak. Look around the pans and see if the fluid is originating there. Look at the rear of the tranny, near the driveshaft. If its wet there then the rear seal is bad and it can be replaced by dropping the driveshaft. Look at the front of the tranny where the bellhousing mates to the block. Red fluid means the front transmission seal is bad and the transmission will have to be dropped. Black/ brown means the engine rear seal is bad and that might require pulling the engine or just dropping the transmission to repair. Look at the bottom pulley on the front of the engine. If its wet there then the front engine seal is bad and that might be replaceable with the motor in the car, I don't know.

Also, pop the hood and look at the top of the engine around the rockerarm cover gasket and see if it's wet there, the rocker arm cover is to the left of the intake manifold and is on top of the cylinder head, it has the cap on it where you add the oil. If it is leaking, go get a gasket (felpro is good, don't use form-a-gasket unless you're really good with it) and replace the gasket here. MAKE SURE THE MATING SURFACES FOR THE GASKET IS CLEAN ON BOTH THE HEAD AND THE COVER. Use a putty knife to scrape any old gasket off. While you have the rocker arm cover off, go ahead and adjust the rocker arms cause you have to do that periodically anyways and theres no telling when it was last done. Get a set of feeler gauges and with the motor HOT AND RUNNING, slide the .010" gauge between each rocker arm and the valve. The valves are the little stems you see under the driver's side of the rocker arm protruding from the head. Use the bolt in the middle of the rocker arm to adjust the lash. Small adjustments here, and your shooting to have the feeler gauge slide in and out snuggly. While you're in there, make sure the pushrods, that protrude from the passenger side of the block and make contact with the rockerarms, are covered in oil and rotating. One last thing, since you're running the motor with the rocker arm cover off, you might have oil spraying everywhere if you have high oil pressure.