Not directly answering your question but couldn't resist because I used to live in MH. Anyhow, as improbable as it seems now, Mountain Home had quite a collection of rare muscle cars when I was stationed @ MHAFB in 1981.

In town, there was a guy that had a '69 T/A and a 70 RAIV T/A that he used as daily drivers. There was Cedar Autobody that had a 6bbl Superbird, a cop that had a 70 Charger R/T, Elms Speed Shop had a 69 Charger R/T for sale and there was a guy selling a 67 R/T roller (mint) for $100.

On base there was my 71 Charger R/T, a 72 Roadrunner/GTX Air Grabber 4sp. Dana in Petty Blue, a 4sp AAR in primer, a 69 Mach-1 428 4sp and a Hang 10 Dart.
There also was a dragstrip on base where they raced weekends, weather permitting.

On the other hand, finding a 340 involved searching the JY system in 3 states.

Boise had maybe 4-5 Mopars running around, not including a custom 69 500 Charger that would intermittently show up @ Ann Morrison Park. Fords were everywhere though.