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Old 11-20-2013   #10
WVZR-1
 
Join Date: Oct 2004
Posts: 1,884
Default Re: Speedometer calibration

Quote:
Originally Posted by Pumpman View Post
Gentlemen,
Thanks for the detailed replies. I will investigate and get the right gears for the speedometer pulse driver.
Will the VIN# or other numbers on door jam/console cover give me the code for the original rear axle ratio?
When I bought this 1991 car I assumed it was 390HP. I had read someplace that the upgrade in heads to 405HP did not occur until 92 but the data plate on the cup holder cover says LT5 405HP, 385 Ft-lbs torque, 11:1 compression.
Is this correct?
The "cup-holder" data plate is an "owner added item" - your console label should display a GM3 RPO code. The SPID label is located inside the console lid on the '91. That's the original 3.45 -If you wanted to lift both rear wheels and rotate a wheel one complete revolution if my thoughts are correct then the drive-shaft would rotate 4 revolutions +. If it rotates only three and one/half times then I'm lost. The advertised HP changes occurred in '93. Earlier advertised is 375.

Quote:
Originally Posted by Mystic ZR-1 View Post

Your speed shop guy has his head up his a##!!!
I'd have to agree with this comment!!!!

Last edited by WVZR-1; 11-20-2013 at 11:54 AM.
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