I swapped my rear and Now the car does 120 mph in seconds!
Thread Starter
Joined: Jun 2007
Posts: 764
Likes: 1
From: www.nythirdgen.com
Car: 1987 IROC-Z
Engine: 350 TPI
Transmission: 700R Auto
I swapped my rear and Now the car does 120 mph in seconds!
Ok now that I got you to open the thread here is my problem.
I recently put a posi 4.10 rear into the car and the pick up is amazing... (yes I know she does top out but the engine swap is slated for June).
The problem is the car now does 120 mph in about 5 seconds. What is the problem you ask. Well the problem is I am only doing about 50 -60mph and the speedo is reading 120.
How do I calibrate the speedo on a '91 Z28? The cluster is all electronic????
I recently put a posi 4.10 rear into the car and the pick up is amazing... (yes I know she does top out but the engine swap is slated for June).
The problem is the car now does 120 mph in about 5 seconds. What is the problem you ask. Well the problem is I am only doing about 50 -60mph and the speedo is reading 120.
How do I calibrate the speedo on a '91 Z28? The cluster is all electronic????
Supreme Member
iTrader: (3)
Joined: Dec 2006
Posts: 1,116
Likes: 1
From: Guilford, Connecticut
Car: 1987 Trans Am
Engine: 355
Transmission: t56
Axle/Gears: 3.73
Re: I swapped my rear and Now the car does 120 mph in seconds!
I was gonna ask where you got this rear from, then I read further... lmaosorry, no help here but that was too funny not to say something.
Joined: Jul 1999
Posts: 10,950
Likes: 26
From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: I swapped my rear and Now the car does 120 mph in seconds!
However, since its electronic you need the right part numbers. A search of this forum for "speedo gears" should reveal all.
Supreme Member
Joined: Mar 2002
Posts: 4,812
Likes: 0
From: 62656
Car: 1991 S10 pickup 2700lbs
Engine: 4.3L Z TBI
Transmission: 700R4
Axle/Gears: 3.08 7.625"
Re: I swapped my rear and Now the car does 120 mph in seconds!
so uhmmm i missed out:
where did he get the rear from ?
where did he get the rear from ?
Junior Member
Joined: Aug 2007
Posts: 6
Likes: 0
From: Lake Worth, FL
Car: 84 Trans Am
Engine: 305 HO
Transmission: 700R4 soon to be a TH350
Re: I swapped my rear and Now the car does 120 mph in seconds!
Places to recalibrate PCM:
GM Dealership
Some Tire shops
Most Performance shops that tune
GM Dealership
Some Tire shops
Most Performance shops that tune
Joined: Aug 1999
Posts: 19,282
Likes: 103
From: Lawrence, KS
Car: Met. Silver 85 IROC/Sold
Engine: 350 HO Deluxe (350ci/330hp)
Transmission: T-5 (Non-WC)
Axle/Gears: Limited Slip 3.23's
Re: I swapped my rear and Now the car does 120 mph in seconds!
The poster mentions a 700R4. Check/call the following website for gear info:
http://www.transmissioncenter.net/sp...n_______va.htm
JamesC
http://www.transmissioncenter.net/sp...n_______va.htm
JamesC
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Supreme Member
iTrader: (3)
Joined: Feb 2003
Posts: 2,065
Likes: 0
From: California
Car: 1982 Trans Am & 1982 Corvette
Engine: L-98 with LO-3 induction. 350 CFI
Transmission: 5 speed and vette has 700r4
Axle/Gears: 373's in T/A .. vette unknown
Re: I swapped my rear and Now the car does 120 mph in seconds!
4.10's in a 4l60 ... does the gas gauge go down as fast as the speedometer goes up LOL
Thread Starter
Joined: Jun 2007
Posts: 764
Likes: 1
From: www.nythirdgen.com
Car: 1987 IROC-Z
Engine: 350 TPI
Transmission: 700R Auto
Re: I swapped my rear and Now the car does 120 mph in seconds!
The tranny is a 700R.
----------
The poster mentions a 700R4. Check/call the following website for gear info:
http://www.transmissioncenter.net/sp...n_______va.htm
JamesC
http://www.transmissioncenter.net/sp...n_______va.htm
JamesC
What a great site!! Thank you!!!
Last edited by goomaan; Dec 17, 2007 at 09:39 AM. Reason: Automerged Doublepost
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