Years ago I used to go to a salvage yard between Baxter Springs and Pittsburg, Kansas, just north of the Oklahoma border, and close to Missouri and Arkansas too. I have no idea if it's still there. Could that be the one you're thinking of?
There are two pretty good sources in Texas that have good stuff and better prices than CTC. One is Classic Chevy Connection in Longview. The owner brings a large trailer to many swap meets and other events in TX and OK. You can google for location and phone #. The other is Little Valley Auto Ranch in Belton, TX, aka Texas Exports. The owner puts on a couple of swap meets a year in Belton.
The most amazing salvage yard I ever saw for 55-57 Chevys and similar stuff was right in the heart of Houston on Long Point in the Spring Branch area, probably only 6-7 miles from downtown. This was in the late 90s. The guy had 10-15 acres, built a new building on it, and had probably 150-200 cars. It was a new business when I first went there. I'm guessing 1/3 were 55-57s, the rest were mostly Chevys and other GM cars from 55-67. The guy was only there a year or so. I was simply amazed that it was that deep in the city - and it turned out it wasn't for very long. I don't know if the guy lost a fortune on it, or turned the real estate for a handsome profit.