4.30 gear swap

[2002YellowGTGuy]

I know a ton of threads have been posted about changed from stock 3.27's to either 4:10-4.30 gears. I'm looking for my RPM range increase here. I have a Magnaflow Magnapack catback and I'm concerned with it being to loud at crusing speeds with a higher ratio. I have an 02' GT with AODE. Also if I change to 4:30's then what would my top speed be? I would also need a chip for gear correction, correct? Any insight? Thanks in advance.

 

[Beau]

here is a link that might help


and you will need a chip or a speedcal. the speedcal can be bought from dallasmustang for 100 bucks i think...

 

[fastback brian]

speedcal will change the speedo but will make the trans shift funny. Your car would run well with 3.55-3.73's and an increase in converter stall.

 

[2002YellowGTGuy]

Well it shows at 55MPH in 4th gear I'm looking at 2,830 RPMs. I believe that I run at about only 2,000 at 55 now... hmmmmm. Anybody else with thoughts?

 

[Beau]

in 5th you should be at about 2000 rpm's when you hit 75ish with stock gears..well thats what i'm at with my 5 speed

 

[san~man]

Your only solution is a chip or programmer. Speedcal won't work.

At 80mph with my 4.10's, I'm at 3k rpms. The only time it will come close to droning is around 2k rpms, but the Bassani system hardly drones, and I'm hardly ever at 2k rpms consistently anyways.

Don't waste your time with anything less than 4.10's, unless a poweradder is in your immediate future.