I recall reading in the Bentley that the speedo is set both a % high and a
fixed amount high.  Has to do with legal obligations.  Resetting the needle
will only work for 1 speed, all others will be skewed.  Best to do is use GPS
or other car to get a series of comparison speeds, then make a little overlay
for the speedo face with the proper speeds on it.  Even cheaper/easier,
instead of an overlay just make little stickers to put over the MPH numbers
with the real speed on them.

That would be fun, actually, to have a speedo that read 8, 17, 26, 35 instead
of 10, 20, 30, 40.

Bill Marshall
'85 GL Tiico "Pandora"
Aurora, IL