Anyone running anything higher than 3.73's?

I have been told that 4.09 would be a better gear for my NA combination to keep the motor in the power band.

Vato said:

I remember when my fox body mustangs had 2.81 or 2.83. Going to a 3.08 which were automatic rear end gearing was an upgrade. Obviously everyone went 3.55 due to the low 225hp. I always thought 3.31 was a good in between gear. That's what I have on my car now and with 450hp, more than enough gear. At 80mph I'm hovering around 2k rpm. IMO, I wouldn't go any higher and more so if you're throwing a blower on there.

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At 70 I am cruising at around 1800 with 3.31's, honestly find myself using 5th at that speed. I really think 3.55's would be perfect for this car.

Roadway 5.0 said:

@SVT-DADDY

What's your outlet? If you drag race on slicks every weekend get the 4.09s; hell go to the good old 4.56s if you have an automatic.

If you're the daily driving type, 3.55 is the max I would personally have on a supercharged 5.0 S550. In your specific case, I would leave your stock gears alone and put the money into the blower fund.

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Just a street car. lol Part of me thinks if I add headers and gears I might be happy enough to avoid the cash outlay for the blower!

TheHydro said:

I had 3.73s and once I put my whipple on it was too much so I went to the 3.31 and the power is much more useable now.

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That's exactly what I am worried about!

I will swap you my 3.73 if you want, I think 3.31's is what I need.

TooSoonJunior said:

I will swap you my 3.73 if you want, I think 3.31's is what I need.

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That's not a bad idea. Let me know.

Back in the late 90's and early 2000's, running 4.30's in a NA Cobra DOHC was the balls...

I did it in my 96 Cobra; sure beat Ford's piss poor selection of 3.08's in a vehicle where spinning that DOHC to a 7,500 redline was easier than baking apple pie... not to mention a POS T45 that couldn't even handle the DOHC redline...

After installing the 4.30's, I could start out in 3rd gear (LOL) without hesitation...but as a matter of fact and believe it or not, my overall gas mileage actually improved after the 4.30's, because the car was not "lugging" as it was with the factory 3.08's.

I wouldn't recommend 4.09's (let alone 4.30's) on a vehicle that is going to be running forced induction and already has a transmission (MT82 or 6R80) that has very good gearing already - too much rear gear, which will only result in massive tire spin (or breaking of parts if the car is sticky and can be hooked).