It was with my old ported '452' OEM heads, where I went from 1.5s I&E to 1.6s I&E and saw zip / nada / zilch show up at the track. I was really expecting some improvement, but... nope. It's not apples to apples, but it's at least one experience where more ratio got me nuttin'.
Intake-only 1.6s did show something like 5 HP w/ the Stage VIs on the dyno, but I ended up sticking with 1.5s on both I&E once the engine went into the car. The 1.5s went with the Stage VIs when they were sold.
When buying new rockers for the Victors, I went w/ 1.6s to go along with the switch to a solid roller. Fully loaded against a "real" spring they're 1.54-1.55 with a net (after lash) lift of ~ .650" w/ the RX roller.
2021 Challenger 6.4L Scat Pack 1320
100% stock: 1.680, 11.894 at 113.75 (DA 175 ft)
weight reduction, wheels, tires, Hellcat air box: 1.661, 11.686 at 115.97 (DA 710 ft)
1973 Challenger 452 ci street/strip [2008]
pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
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