OK, here's the situation:
I have an 88 iroc with a 9-bolt
No Codes on glove box to see what originally came with the car
I put it on a lift, had a friend spin the tire one full revolution - the driveshaft spun just under 4 times
Being that this isn't the most popular rear end out there, what could these gears possibly be?

p.s. at about 60mph, the motor is revving about 2200-2300
thanks in advance for all your input!


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-80 Camaro 350, Carter AFB, headers, dual exh, ram air, all sorts of crap
-88 Iroc-Z 350tpi, 3.27 gears, 4 wheel disc, MSD 6a, tpi airfoil, k+n's, white gauges, accel coil, flowmaster, pretty quick

 

well from looking at your sig i'd say 3:27 gears

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ICON Motorsports

1st & 3rd

 

Just under 4 turns and running at 2300 RPMs sounds like 3.70's to me. Get up to 75 MPH safely on the freeway in drive (not overdrive) and read what your RPMs are. For my 3.45 rear end I'm at 3450 RPMs. If you had 3.70's you'd be at 3700 RPMs. Make sense?

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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=-

 

3.27 was common. 3.45 was also available. If you have 3.70 then consider yourself lucky. The previous owner must of had them installed.

Kevin: It only makes sense if he has the same height tires as you do. If not then the rpms will be off. SHould be close enough though.

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Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z Pro ET Bracket Race Car
383 stroker (carbed) with double hump cast iron heads and pump gas
461 Big Block installed and ready for the 2001 racing season

Best results before the 383 blew up
Best ET on a time slip: 11.857 altitude corrected to 11.163
Best MPH on a time slip: 117.87 altitude corrected to 126.10
Altitude corrected rear wheel HP based on power to weight ratio: 476.5
Best 60 foot: 1.662

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley