Billy182

Just wondering who may have done rpm’s 390 gears and what were your impressions?

TRSCobra

Pros: makes the car snappier, more ideal for 1/4 mile (if NA), can help big cam drivability a bit.

Cons: harder to find traction on the street, cuts your 4th gear top speed down a good bit for roll racing or half mile stuff.

polyol

I have it. Love it. What do you want to know?

polyol

I did it more for Autox. 2nd gear is now a beast for Autox, before it was too tall and unresponsive.

Sicvette

One of the best mods I’ve done. Love it for the street.

polyol

Yeah, the 3rd and 4th gears are just magical. Hehe

Last 1

first ? are you NA if so by all means go for it. your only problem is keeping the smile of your face for doing it .I was running 4.10s in my car and moved up to 3.90s with my car if I decided to run NA I can run a 26” tire and go thru the traps about 140/and if I decide to turn my bottle on i can go to my 28” and try to shove it thru @ 150(1/4 mile)

amdoverclocker

I'm actually sending my trans and diff out to RPM tomorrow! Haven't decided what ratio I want to go with yet though.

H8VTEC

I'm running 3.90s with thier stage 4 diff. You'll be at the top of 4th in the 1/4 when before you were top of 3rd, bottom of 4th. You'll be top of 3rd in the 1/8th on a 26 inch tire. If you have a big cam it makes it easier to drive in the street as well. From what I've been told by rpm, if running a 26 tire go 3.90 of 28 go 4.10.