Have a few questions:
1)Can the speedo be recalibrated? Or how far off will it be?
2)What increase can i expect in RPMs (currently tachs 1900 at 80mph in 6th).
3)How top end will i lose?
Any information is appreciated.
This is a little fuzzy, but here goes. If you're taching 1900 @ 80 mph in 6th (and if I recall correctly that 6th is a .56 ratio) then your speed at 1900 rpm with 3.73 gears would be about 73.4. This is based on a 27 inch tire diameter, rear ratio 3.73, trans ratio .56 at 1900 rpm.
To add to that info: the 3.73 is 9% shorter than the std 3.42. At 80 mph in 6th, if you're currently @ 1900 rpm, you'll be at 2072 rpm with the 3.73, roughly a 170 rpm increase in this case. You should have better acceleration across the board but two things to keep in mind:
1. 100 mph will no longer be achievable in 3rd; top speed in 3rd will be about 92 mph.
2. Ultimate top speed will be reduced to somewhere between 157 and 160 mph, before fuel cutoff in 5th.
6th will be a more usable gear, but still too tall for any meaningful topend.