1988 corvette 700r4 transmission/Gears
 

How do you no what gears are in your car? Posted code door or glove armrest ? I have stock 17 wheels loaded model better suspension z51, I want to put 3.73 gears master installation kit, racing shop says change Governor ,springs and weights higher the revs lighter the springs and weights have to be changed for correct shift points that I understand.the question here is the housing for 2.59-3.07 gears are they different?sonnax makes a calibrated governor THAT'S all set when you changed it or go with kit weights and springs versus by a new Governor $55. I have yukon pinion gear thick dana 36 iac rear. The transmission 700r4, 3.73 and master installation kit 2 quarts of gear oil going have racing shop do it but how do I find out what gears are in it now 2.59-3.07 because 3.07 was optional? Than you MrLuper

IF you have the original glove box, I would think the sticker is under the lid. Should be a bunch of 3 letter codes.

https://www.corvetteforum.com/forums...4-rpo-faq.html

G44 - 3.07 Rear Axle Ratio
G87 - ring gear 8.50 inch
G92 - Performance Axle Ratio
GHO - 3.54 axle ratio
GM1 - 2.59 Rear Axle Ratio
GM3 - 3.45 Rear Axle Ratio (8.5 in. Ring Gear)
GT7 - 3.33 rear axle ratio
GU2 - 2.73 Rear Axle Ratio

If you presently have a 3.07 and it's very likely you do, you would need to get a D36 with a 2-series rear axle ratio because I doubt there are any D36 builders that do a "thin gear set" for the 3.07 carrier to take it to 3.54 or 3.73. If you find you have a 3.07 and you're dead set on the change don't disassemble the 3.07, consider selling it as is and build another. You'll save considerable money.

Post a snapshot of your SPID label that is hopefully on the console door still!

Just Differentials at one time offered a 3.73 "thin geat" and it still shows on their website but who knows if that's actually correct. You might call and ask, they still show a "thin" 3.54 also.

http://www.justdifferentials.com/D36...d36-373-ng.htm

If you're going to swap differentials, I think I'd go with a Dana 44. That way the higher gear ratios will fit without resorting to the thin ring gear. The reason for using the thin ring gear is that the standard higher ratio ring gears will not fit in a Dana 36 case. I believe the Dana 44 cases are more robust as well.