Mine were 10 for 10. 68-71's were it. the 72-73 were dogs. But I did have a stock 72 put a cam in, headers and a model j conv. and it went 12.90 with 7" slicks & 4.10 gear, Duster 3300 + 200 for me. And my 68 4 speed ran to 6500+, the only change was to a 750 carb. I never found one that was mechanically sound that wouldn't run. But I tuned them my way. And no damn 87 octane. I don't like the Wallace calculator I use the ones from Mopar in the 60's - 70's.