I now run JR1 Racing Oil JR 4.0 5/20W full synthetic. I began running it in my 5.7l G3 Hemi super stocker and then ‘snuck’ up on running it in my supercharged 354 stocker motor.

I have run many oils over my 37 years in all my various Mopar based race engines and sometimes wondered if there was a big difference as long as you stuck with a top quality synthetic with decent additives. In the case of this JR1, it consistently made 7-12 HP more on dyno pulls across the power band and after having made more than 20 passes with the supercharged 354, BES tore the motor down and called me to say I was lying ... it didn’t look Iike I’d made more than a couple passes. It’s good stuff and the cheapest horsepower I’ve found yet.