I have a 89 Pontiac Formula 350 with the L98 but I would like to find out what the gear ratio in the car is. I can no longer see the sticker on the rear axle cover, but I do have all of the codes in the middle compartment storage area. What are the codes I am looking for??

 

Any answers????

 

The code will either begin with GU or GW depending on if you have the 10-bolt or 9-bolt rear. GU2 is for 2.73 gears in a 10-bolt. I think there is something on thirdgen.org that lists all of the RPO codes. If not, they're out there somewhere on the 'net. BTW, G80 is for posi-trac.

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Greg Westphal
'87 IROC 305TPI/A4

 

if you pull the cover you'll find the gear ratio stamped on the ring gear. it'll be like 11:41. thats 11 teeth on the pinion and 41 teeth on the ring gear. 41/11=3.73 or a 3:73 gear set.

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For an 89 350 its really easy to tell. If you have a single cat, you have a 9-bolt 2.77 ratio. If you have dual cats, you have a 9-bolt 3.27 ratio. No other rears were offered for 89 L98's.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.25 @ 107.18 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
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