I know a few of you had them. Unfortunately I sold all of mine when I moved into an apartment, and had to empty the parents back yard. LOL
I had a 1972 240Z, had the original faded blue metallic pain with some hideous rear window louvers. Grey primer spots all over the body, the car looked like pure crap. Under the hood though lay a beautiful I-6 L24 block, bored out, with a late model 280Z head milled to the hilt, ported, polished, Chevy valves, a nice high lift ISKY cam sat under the cover. Tilton dual disk clutch, on a lightened flywheel, MSD ignition, triple side draft Delortos. The car got 9 miles to the gallon on a good day. Tri-mil equal length headers, 2 1/2" pipe to the rear with a glass pack. Car also had full poly urethane bushings, with Tokico 5 way shocks, and motorsport springs.

Most people would hear the car lopping at the light, and just figured it was pos with a bad miss. But when the light turned green there was no catching the little beast. I walked 5.0 Mustangs, and a few classic camaros. I lost to a vette once. I knew it was pumped, I was just hoping for luck, and it was not with me. He didn't spank me, I certainly surprised the eff out of him though LOL.
I also had a 23 window rag top bus, that would do high 12s to low 13s in the quarter. Used to cruise it to the swap meets at Sears Point (infineon) with the needle tapping the 0 peg

(approximately 100).
I also had a 67 GT390 4spd Fastback Mustang, but it was not a sleeper. It looked fast, sounded fast, and was fast LOL.