1967 GT500 Axle Ratios and information on Posi Traction

Mike,

'67 G.T. 500s came with 31 spline open rear ends. I think the stock ratio for use with an automatic transmission was 3.25:1. I'm not sure if air conditioning has an effect on ratio. The case should be a non-N nodular (identified when you remove the housing by the casting number C4AW-B ). As to what to put in its place, I'd use a four pinion Traction-Lok, with ratio of your choice (personally, I'd stay close to stock).

Give John a call at Perogie Enterprises (609-448-1684) and he'll set you up.

 

My car (manual trans)came with a 3.50 gear and I tried a 4.11 with a mini spool for a while in the late 80's. That was no fun on the highway or in the rain. I would stick with a gear close to stock and like Roy said go with a traction lock. Should not be hard to find at a swap meet.

 

I went with a 3:50 posi using my original "spec" cast carrier .

 

That original "spec" carrier may in fact be the famous nodular iron case without the "N". See my above post to ID. That's what was in my car when I took it apart and still is.

 

I would also recomend a Traction Lok with your stock gears for a driver...I use a Gold Trac differential in my 350, it great but very exspensive, A locker in my Eliminator is a little noisey, and a traction lok in my 68

 

I went with 3.91's in an N case and shelved my original 3.50 pumpkin. It really woke the car up. Not great for long freeway trips, so it depends what you are doing with the car.

 

3.50 is a good all around gear. No problem doing trips of 100 miles or less. Definitely get a locking rear end - the Ford traction lock should be fine.

If it was me I would have somebody rebuild your current rear with a 3.50 gearset and traction lock. Will still look stock from the outside.

 

I know it is a picky annoyance but I would like to thank the posters who use the correct Ford term of Traction Lock and not the GM licensed term of "Posi-Trac".