Rear end gears, stock?
Thread Starter
Instructor
Joined: May 2004
Posts: 103
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From: Peoria IL
Rear end gears, stock?
I know 3.70 is recommend for good acceleration without robbing your top end and is a good overall even ratio. My question is, what is the stock gear ratio? I'm pretty sure mine is stock, if not, how can I find this out? It is a 1977 TTop AT. Thanks
Bry
Bry
Drifting
Joined: Nov 2003
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From: Northern NJ
St. Jude Donor '04 & '05
Re: Rear end gears, stock? (Bryan52803)
Can't speak specifically for a 77, however my 75 manual indicates that with the L-48 engine and a AT, the standard ratio was 3.08 with an optional ratio of 2.73 available. With the L-82 engine and a AT, the standard ratio was 3.36 with an optional 3.55 available.
To find out what ratio you have, you can always jack up both rear wheels and rotate one of the tires, counting the rotations it takes to achieve one rotation of the driveshaft. You should be able to count the number of tire roatations close enough to determine which one of the ratios you have.
Hope this helps.
[Modified by ACECO, 1:10 AM 6/27/2004]
To find out what ratio you have, you can always jack up both rear wheels and rotate one of the tires, counting the rotations it takes to achieve one rotation of the driveshaft. You should be able to count the number of tire roatations close enough to determine which one of the ratios you have.
Hope this helps.
[Modified by ACECO, 1:10 AM 6/27/2004]
Melting Slicks
Joined: May 2002
Posts: 2,508
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From: Wisconsin
Re: Rear end gears, stock? (Bryan52803)
My L48 AT '77 came with 3.08s. On the top of the rear end cover it should have a sticker that says "AO7" for 3.08s. I think that's right. Another easy way is to just read what your RPMs are at a speed and know your tire diameter. Then just enter it into a calculator such as this one: http://www.idavette.net/tech/ratioc.htm
If you don't know your tire diameter, enter the info from the sidewall into this website to get the diameter. http://www.miata.net/garage/tirecalc.html
If you don't know your tire diameter, enter the info from the sidewall into this website to get the diameter. http://www.miata.net/garage/tirecalc.html
Team Owner
Joined: Sep 2003
Posts: 88,393
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From: eville in
Re: Rear end gears, stock? (Schmucker)
3.70 gears are on the edge of both (everyday/perforance) 
I allways liked 3.90's i could get out of the hole even with most and run past
them in 3rd or 4th on the top end
I allways liked 3.90's i could get out of the hole even with most and run pastthem in 3rd or 4th on the top end
