I am going to rebuild the posi and while i was in there i figured i would change to a more desirable gear ratio. What kind of difference would there be in switching to 373 gears? thanks for any info

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Red 87'Z-28 350 tpi,MSD ignition 6al,gutted maf and airbox,
700r4 w/b&m shift kit and cor. servo

 

it'd help to know what gears you have in the car now?

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ICON Motorsports

1st & 3rd

 

With an 87 350 you have either 2.77 or 3.27, both 9-bolt rear ends. If you have 3.27's you can get 3.70 9-bolt gears, but if you've got 2.77's you're out of luck.

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West Coast GM Shootout 2001!
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
-=ICON Motorsports=-

 

okay sorry i should of stated that the car origionally came with a 305 and a 10 bolt rear end (as i was told)..can you tell me with that info i dont have any rpo codes or anything....?

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Red 87'Z-28 350 tpi,MSD ignition 6al,gutted maf and airbox,
700r4 w/b&m shift kit and cor. servo

 

Ok, with a 10-bolt and a 305 automatic you probably have 2.73's. What are your RPM's in drive at 70 MPH?

Yes you can put 3.73's in there, but with a stock TPI, 3.42's would be better. TPI doesnt pull at high RPMs.

 

At 70 mph the rpms were slightly over 2750( the needle was alittle over the middle mark between 20 and 30)and i am planning on adding a borla full cat back with headers and nitrous soon so which gears do you think i should go with 3.42's. Thanks

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Red 87'Z-28 350 tpi,MSD ignition 6al,gutted maf and airbox,
700r4 w/b&m shift kit and cor. servo