What 'inch' gears do I have?

[usamuscle892]

Im wanting to drop some 4.10 gears in my car but it would help knowing whether I have a 7 1/2" or 7 5/8" rear-end. Im running just the stockers and I was also wondering if someone could tell me what I ratio Im running now.

[wolfdogs]

do you still have your list of codes for the content?

dont know about third gens, but 4th gen's dont do well with 4:10 in an autotranny car...

[Joe 1320]

Im wanting to drop some 4.10 gears in my car but it would help knowing whether I have a 7 1/2" or 7 5/8" rear-end. Im running just the stockers and I was also wondering if someone could tell me what I ratio Im running now.

Short of pulling codes as mentioned, it's going to be tough. There were several different rear ends used in 3rd generations. You could even have an Australian 9 bolt and those are durable but harder to find parts....... That being said, you really don't want 4:10 gears for that unless you've done severe modifications to the engine. Your torque is better suited for taller gears.

[95TransAm]

That being said, you really don't want 4:10 gears for that unless you've done severe modifications to the engine. Your torque is better suited for taller gears.

100% agree.

I knew a guy who had 4.10's on his 92 firebird with a 305. He basically got the gears for free from someone else who was parting out his car. I can first handedly say those gears are no good for a stock 305 a4. He actually wound up putting back in his stock gears because he just couldn't stand them anymore.

In my opinion, your better off getting 4.10's once your engine is built up a bit. If you don't plan on doing that, then go for some taller gears like Joe said...3.73's, 3.42's, or even 3.23's might be better suited for your ride.

[Mark B]

I have the same engine/car as you do and I can tell you.... 4.10's will be way to much gear for your car. I put some 3.73's in my rear. 2 weeks later I pulled them out & replaced them with 3.42's MUCH BETTER! And I still felt a good increase in power with the 3.42's over the stock 2.73's.

[Benm109]

Im wanting to drop some 4.10 gears in my car but it would help knowing whether I have a 7 1/2" or 7 5/8" rear-end. Im running just the stockers and I was also wondering if someone could tell me what I ratio Im running now.

If your rear end is totally stock (you never know what the previous owner could have done), than it should a 7 5/8" 10-bolt with 2.73 gears, 28-spline axles, and an open differential. You can also check your RPO codes to see what came stock in your car. Even with all that said, I'd still double-check everything by pulling the diff. cover and actually looking at what you've got.


The 7 1/2" and the 7 5/8" are pretty much the same thing, a 10 bolt rear end. The other common rear end in the 3rd gens (usually the higher end cars, like the Z28, Trans Ams, etc.) is the 9 bolt (7.75"), but parts are very scarce for them. The 3rd and last rear end available in some 3rd gens was the Dana 44, but it was only found stock in the 89 TTAs and the 91-92 Firehawks, but was available through GM Performance Parts at the time so anyone could have installed it in their 3rd gen.

[brynnda]

its a 7.5 i just bought gears for mine yesterday

[usamuscle892]

Sorry I didn't post again sooner guys, I got busy with school/work. Anyways, I guess, atleast in this case, more isn't better. I want the car's performance/pull to be stronger and I just automatically thought something as low as 4.10's would be great. I'll definetly forget about those and go with something higher. Thanks for letting me know about the 7.5 size. As far modding the engine, I plan on doing a used 350TPI swap or just getting the Accel/Lingenfelter Super Ram Street TPI conversion kit for my TBI. Other plans.....aluminum driveshaft and of course some lower gears so I can feel what money I do put into the engine.