i have a 91 z28 5.7 with the g90 performance axle does any one no what gears i would have come with

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91 Z28 slp headers adj reg accell cap rotor coil comp cam roller
random tech cats flowmaster catback

 

Here is a trick that works regardless if they have been swapped or not.

If you have an auto, put it in D (3rd) and if you have a manual, get it into 4th and do 70 MPH. Then look at your tach.

@ 70MPH:

2.73 = 2730 RPM
3.08 = 3080 RPM
3.42 = 3420 RPM
3.73 = 3730 RPM
4.10 = 4100 RPM

See where this is going? Just count one digit over and put a decimal point there and thats your ratio.

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That is a pretty slick way of finding the ratio!!!

 

its just basic math. auto 3rd gear and standard 4th gear are 1:1 ratio.

 

What tire diameter is that formula based on and how much does tire diameter effect the results of that formula?
What about convertor slippage?
Thanks

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LOBC-- SS-84

92 RS Heritage package with a 305 3" high-flow cat and pipe with a Dynomax 3" in dual 2 1/2" out.

84 El camino- 383 CID, Performer RPM, GMPP vortec heads, Holley 750 D.P.(0-4779c), Crane Energizer 274,Dual 3" Flowmaster 40 Series Exhaust, Turbo 350 (375b), TCI 2500 stall, Richmond 3.42 gears, PST Poly graphite Suspension bushings, PST steering linkage, PST springs, Monte SS sway bays, Wheels from a Third gen(does that count?)

 

your converter should be locked up at highway speeds

 

I was mainly asking those questions so if I go to buy any car that i could use this trick formula. Say like a first gen or an older A-body.

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LOBC-- SS-84

92 RS Heritage package with a 305 3" high-flow cat and pipe with a Dynomax 3" in dual 2 1/2" out.

84 El camino- 383 CID, Performer RPM, GMPP vortec heads, Holley 750 D.P.(0-4779c), Crane Energizer 274,Dual 3" Flowmaster 40 Series Exhaust, Turbo 350 (375b), TCI 2500 stall, Richmond 3.42 gears, PST Poly graphite Suspension bushings, PST steering linkage, PST springs, Monte SS sway bays, Wheels from a Third gen(does that count?)

 

Tire Diameter should not affect it much, atleast not enough that you cant determine what it is.
ie if you are turning say 2800 rpms you should be able to figure out that you are running 2.73s

 

All 90-92 L98's come with automatic transmissions, G92 performance options, dual cats, and 3.23 gears.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
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