Rear Differential Gear Ratio

[phaZe]

I'm having trouble figuring out the rear gear ratio. My manual for the car says the code on the left side of the axel should start with 2 letters, but mine says this "8AH 0 127". It doesn't follow the format it gives as "the standard" for rear axles.

If I look up AH it gives 2.29 as the gear ratio, but with it not having the same format I was curious if it is correct.

 

[robnoxiousauto]

every g body I ever got has had 2.29 with a 305 4bbl and turbo 350 so yes I suspect that is the gear ratio for you're car you poor b*st*rd. I would suggest dropping the ratio to aroul 3.07 with a three speed trans perhaps that will also fix ur speedo issue

 

[phaZe]

Well, the transmission could have a different speedometer gear set than what was put in the stock trans. Some people have told me if it was ever worked on by a transmission shop they easily could have swapped it out to make the job quicker and get more money for less work. It also could have just had the transmission replaced all together. I need to pull out the speedo driven gear and count the driven gear teeth and find out if the driven gear is correct or not. I've heard having just one tooth off can change it 3mph at lower speeds and even more at higher speeds.

Thanks for confirming that for me, 2.29 seems really crappy though, but it's not like I'm racing it or drag racing it right now so I don't really need to swap it out or the transmission.

 

[Chevyman85]

Yeah, the toothcount on the speedo gear makes a huge difference. If your spedo is off at low speeds it will be far more drastic at higher speeds. It increases exponentionally.