Which Speedo Gear?

[Mustanganatic]

I've got a '94 Cobra Pace car and I'm planning on putting in 3.73 gears. Obviously going to have to change the speedo gear. I called CJ Pony Parts and their calculator said it's a 23-tooth gear. I checked the Summit website and it said it needs a 21-tooth gear. I believe it's got a T-45 in it and I read in the Modded Mustang forum the Cobras have a 7-tooth drive gear while the GTs have an 8-tooth. Perhaps that's the reason for the discrepancy between CJ and Summit. Anyways, does anyone know what speedo gear I need for my application? :shrug: Thanks!

 

[Mustanganatic]

I found this on the Ford Racing Parts site http://www.fordracingparts.com/download/charts/129.pdf I guess I just need to verify that the Cobras have a 7-tooth drive gear.

 

[Mustanganatic]

FYI. I'm sure there are many out there that have done a rear end swap and run into this problem. But for those of you that may be planning a swap in the future, this is what I found. Contrary to what that thread in Modded Mustangs said, it is a T-5 tranny in the '94 Cobra and I'm betting it's an 8-tooth drive gear. I got the gears in with a 21-tooth driven speedo gear. My speedometer is still off by 10%. The Ford Racing catalog link that I referenced in the beginning says that a 3.08 ring gear will have a 20-tooth driven gear with an 8-tooth drive gear. The driven gear I replaced was a 20-tooth, that's why I'm pretty sure I have an 8-tooth drive gear. Mustangs Unltd. has a speedo gear kit for the T-5 with a 3.73 rear end which is just a 7-tooth drive gear and a 21-tooth driven gear. It claims it is the most accurate combination. You can get these speedo gears much cheaper right from a Ford dealer. The part nos. are in the link. The bad news is that you need to pull off the tail shaft to get at the drive gear