There should be no difference in the gearing of the right angle drive. However, each speedo is tailored to a particular axle ratio revealed by the code on the face of the speedo e.g. 6322/09 . There is a list on the stickys in the technical info on this board which tells you what each speedo is designed for . If, however, your problem is 20kph overread at all speeds, rather than getting progressively bigger as you go faster, then it is unlikely that it is just a speedo mismatch
Edit : here is heuer's original posting on the subject
I found the table below in the Jag-Lovers archive detailing speedometer serial number, turns per mile, axle ratio and tyres. You will see Jaguar produced a wide range of speedos for various applications. The list is missing some TPM figures so if you have one of the listed speedometers and can provide the TPM figure (will be on the right hand side of the needle boss) I will include them.
Series 1 3.8 - All fitted with 6.40x15 RS5 tyres
Number; TPM; Diff; Calibration
SN 6322/00 ; 1216; 3.31; mph
SN 6322/01 ; 760; 3.31; kph
SN 6322/02 ; 760; 3.31; kph (Germany/Italy)
SN 6322/03 ;1312; 3.54; mph
SN 6322/04 ; 820; 3.54; kph
SN 6322/05 ; 820; 3.54; kph (Germany/Italy)
SN 6322/06 ;1086; 2.93 ; mph
SN 6322/07 ; 678; 2.93 ; kph
SN 6322/08 ; 678; 2.93 ; kph (Germany/Italy)
SN 6322/09 ;1120; 3.07; mph
SN 6322/10 ; 700; 3.07; kph
SN 6322/11 ; 700; 3.07; kph (Germany/Italy)
Series 1 4.2 - various tyres as specified
Number; TPM; Diff; Calibration;Tyre
SN 6322/00A; 1216; 3.31; mph; 6.40x15 RS5
SN 6322/02A; 760; 3.31; kph; 6.40x15 RS5
SN 6322/03A; xxxx; 3.31; mph; 6.40x15 SP41
SN 6322/05A; xxxx;3.54; kph; 6.40x15 SP41HR
SN 6322/09A; 1120; 3.07; mph; 6.40x15 RS5
SN 6322/11A; 700; 3.07; kph; 6.40x15 RS5
SN 6322/13; xxxx; 3.31; kph; 6.40x15 SP41
SN 6322/14; xxxx; 3.54; mph; 6.40x15 SP41HR
SN 6322/27; xxxx; 3.31; mph; 6.40x15 SP41HR
SN 6322/28; xxxx; 3.31; kph; 6.40x15 SP41HR
SN 6322/29; xxxx; 3.54; mph; 6.40x15
SN 6322/30; xxxx; 3.54; kph; 6.40x15
SN 6322/31; 1020; 2.88; mph; 6.40x15
SN 6322/32; 638; 2.88; kph; 6.40x15
SN 6322/33; xxxx; 3.07; mph; 6.40x15 SP41
SN 6322/34; xxxx; 3.07; kph; 6.40x15 SP41
SN 6322/35; xxxx; 3.31; mph; 185x15 SP41
SN 6322/36; xxxx; 3.31; kph; 185x15 SP41
SN 6322/37; xxxx; 3.54; mph; 185x15 SP41
SN 6322/38; xxxx; 3.54; kph; 185x15 SP41
SN 6322/39; xxxx; 2.88; mph; 185x15 SP41HR
SN 6322/40; xxxx; 2.88; kph; 185x15 SP41HR
SN 6322/41; xxxx; 3.07; mph; 185x15 SP41
SN 6322/42; xxxx; 3.07; kph; 185x15 SP41
If you want to work out the expected speed from different axle ratios, gearboxes and tyre sizes, 5Speeds.com has a neat downloadable calculator:
http://www.5speeds.com/rpm.htm which is fun to play with! Another online calculator is available here:
http://wahiduddin.net/calc/calc_speed_rpm.htm
If anyone fancies a DIY approach to speedometer calibration Mike Frank has an excellent write up on his site:
http://www.westnet.com/~mfrank/Speedometer/Smiths.html
The SBM Society also has a good write up on speedo repair and calibration.
http://www.sterlingbritishmotoringsocie ... Repair.pdf
_________________
David Jones
S1 OTS OSB.; S1 FHC ODB #860294