Well, I went from a stock 2.73 (2.77?) pegleg drum brake rear on my 91 Firebird Convertible to a 94' Z28 3.23 rear with posi and disc.

First of all, it is *much* quicker off the line and the rear disc brakes are awesome. I don't think I will need to get a proportioning valve as the brakes work great!

My question is the speedometer gearing - I assume the stock drive is red 17 right? Which means I probabaly have a 36 drive gear. From the transmissioncenter.net website, it says I need a speed sensor (white) if I go to a 43 driven gear. Anyone help me with this? Do I need the sensor ($56) too?

The other option is get both gears which I think is a 15 (grey) and a 39. How difficult is it to change the drive gear?


I'll have pics up in a week or so. I have new rims also to fit over my new hardware. Funny thing is the rear disc. They are HUGE compared to my stock front disc...lol...

 

I think we know what THAT word becomes, when you break it down into its component parts...

It's not hard to change the drive gear; the tail housing unbolts with 4 bolts, and the gear is right there. Still, it's enough of a PITA that I'd look for ways to only do it once; i.e., get all the right parts in advance, and have them on hand, BEFORE busting into the transmission, rather than getting halfway through and realizing you need some piece that you don't have.

 

LOL...yea I am going to take off the cover and verify the drive gear is indeed a red 17. The other option I saw was a box that splices in the VSS and converts it electronically. I may go that way - it is $150, but I can change ratios on the fly.

 

You don't have to change to a white VSS, i did the swap to 3.42s and used the black VSS with the new gears.