This will make everyone sigh but my co-worker bought a Le Mans blue/black vinyl Yenko in '72 for $2000. 30,000 miles; still had the AIR system. All that came off immediately; headers, glass packs, T-bars. Still one of the fastest street cars I experienced. It was his daily driver and was eating him alive between the gas and insurance so it was sold [$2200!] and a more tolerable '68 Camaro SS350 replaced it. Took several weeks to sell it. It's still around with OE engine but needs resto. N615046 for you numbers guys.
So you're correct. Gas was much cheaper in '72 but $10,000 was a good annual salary in those days.