Originally Posted by
JDNSW
The 1400 and 1500 are the revolutions per mile (of the speedo cable). The 1500 will be off a swb and the 1400 off a lwb, but they really refer to the tyre size - standard 6.00x16 on the swb and 7.50x16 on the lwb, or 28" and 31" overall wheel diameter respectively.
Which is the right one for you depends on what size tyres you plan to run.
I would be very cautious about using anything on the odometer except water with a little detergent added, and even then, be very gentle.