I am attempting to bleed the brakes on a 70 Challenger. It has power drum brakes. Everything seemed to go ok until I got to the last wheel on the driver front. I kept bleeding and kept getting air. I double cheked all fittings to be sure they were tight. I have a new wheel cylinder and hose. I can get a pedal if I pump it up but that is it. Any ideas?

I would look at the combination valve first. If you have a spare out of the car, you can inspect it to get an idea of how it works. I am more familiar with A body cars, but most are similar in concept. The front brake line from the master cylinder connects to the combination valve. Inside, the fluid goes 2 directions: The left front wheel and the right. If the valve is in poor condition or has any dirt, rust scale or any other contaminates inside, it may be impossible to get all the air out.
Also, it may help to have a friend to look underneath the car as you pump and bleed the brakes. Look for leaks. I'm sure that you are bleeding them with the engine running, right? The power assist will be needed to properly do the job. 40 year old brake lines and valves can work fine or leak like a screen door. Its a good thing that there are repops available.

The master cyl, brake lines and wheel cylinders are new. It is the original prop valve. I have blead rr,lr,rf and lf. I did not have the car running. There is no air on the other 3 wheels, just the lf. I was using the old hose in a jar method but did not close bleeder after each down stroke. Worked ok on other 3 wheels just not that one. I know the air is comming in somewhere. I will try these suggestions today and see what happens. Thanks.

The bleeder screw may be a bit more unscrewed on the LF and or the screw threads may be a bit more looser so air is getting by the threads and it's easier for it to draw the lighter air in than the heavier fluid. If you have a helper you might have him close that particular one right before the upstroke.