Line lock for parking brake?

Wheel chock(s) in trunk?

 

You hit the nail on the head. (but??d.)
But.... the performance is questionable, erratic, not really a positive, reliable parking brake unless the driver is in the seat prepared to use service brakes. I had an airplane with parking brake like that sand rail device. Designed for momentary hold when driver was in the seat. If it was left on in hot weather, thermal pressure buildup could damage system seals. If it was set when the brakes were warmed up from operation, in a few minutes, the pressure lowered and the brakes weren't locked anymore. For on the spot, temporary holding, as on a hill. Otherwise a bad idea.

Good idea, seperate E-brake.

 

Even a micro lock is not legal in hydraulic brake trucks anymore.( after you chase a tow truck that released one time you would never use one again...that sucked) You need a stand alone mechanical operated brake. Or blocks in front and back of the tire.
All the work you did change the rear.

 

For Pete's sake. The answer is obvious. Dump that antique rear end for something built in the past 50 years or so and use a conventional, cable operated brake. Using that old Plymouth unit with it's marginal brakes and tapered axles is pointless. What kind of gearing does it have? I'm betting it's way too low for highway cruising. As I aked earlier, isn't one of the mid size MoPar rear ends almost a bolt in? Volare, Duster, Dakota???

 

Carl, a late 60s B body axle is just about right, but the spring pads are too wide.
Fairly easy fix, cut them off the old one and weld to the new(er) one.

Heard that Cherokees work too. Don't know exactly what is needed.
Explorer has been mentioned too, w/Discs.

This is the same thing all budding hot rodders have done thru time; add power then try to skate by with stock brakes. Like the others here that have warned you , put some time and money into stopping too!

 

Yep! I run those on my wrecker and have for years. awesome product.

 

You'll fix it right after the first ime you find your car a block or two down the street.

 

Im 72, first thing I learned was how to stop it, and then learned how to make it go. NO short cuts for brakes.

 

Yeah, we had both electric and manual lever brake locks on the tow trucks I drove years ago. Worked great for a little extra while you were winching but as a parking brake... no. They wouldn't hold over night as I found out one morning when the slider with 2 cars on it wasn't parked in front of my house anymore, found it down the hill a bit!