Speedometer calibration

[WVZR-1]

Originally Posted by Pumpman

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.

Originally Posted by Mystic ZR-1

Your speed shop guy has his head up his a##!!!

I'd have to agree with this comment!!!!