rear end question and gears

[austingoblue]

I decided to not use the 2000 rear end from my donor and go with the fox body width rear end so I can use the original style rims. I am ordering the axle and bracket kit from richard at northracecars.com but had a question.

the fox body gear is a 2.73 and the 2000 rear end is a 3.73....I am guessing that I will want to change the gear in the fox body???

and is it possible to switch out the whole set up from the 2000 mustang rear end (the gears) and put it in the fox rear end.

and will the axles fit (I am sure richard will answer this when I call...just wondering if anyone here knows)

thanks for your time....I am picking up the MK4 December 28th!!!

Doug

[Jacob McCrea]

Congrats on the new purchase.

I have no knowledge of the axle issue but am sure that someone else knows the answer.

As for the gears, as long as the differential from the 2000 is an 8.8", then yes, those 3.73:1 gears from the 2000 differential will work with a Fox-width 8.8" differential, as will the carrier/Traction-lok unit. The gears should also work with any other variant of the Ford 8.8" differential you might find: the various IRS units, the pickup truck and SUV units, etc. I say this because have never heard of any difference between 8.8" Ford gears. There are some differences in ring gear carriers between IRS and solid axle applications, but that is a separate issue.

Edit: As for the gear ratios, I have no opinion on what ratio is best for your specific application. But for what it's worth, I have read a lot of posts over the years stating that 3.27:1 and 3.31:1 gears are a really good fit for the Roadster and Coupe's power-to-weight ratio. I think you would get some good advice on that by noting the car's intended use, terrain, anticipated power level, etc.

[Kevin Davis]

I'm running 3.55's in mine, I just had a local shop put the new gears in for me for like $100. I'm running about 260hp/290tq as it dyno'd, and for me, it's a great balance of power to driveability, and I can cruise along at 75-80 on the highway and keep the rpms down.

[SStrong]

It's a good idea to get someone who knows what they're doing to put the gears into the Fox housing. Getting the spacing correct may save you a set of gears. They may have fit perfectly in the old housing but be way off with the switch. $100 is a good price. You're better off going with the Fox, but be aware the axles were 4 lug, so you need to get a pair of 5 lug for the original wheels. They're not hard to switch out. Good luck with it, bet it will work out for you.