If
your speedometer is mechanical and not electronic this should
work to make it accurate. When I had my 32 with the Hemi
in it the speedometer was way slow. Here is how I fixed it
First you have to disconnect the speedometer cable from the
back of the speedometer. You need a revcounter like the one
shown in the picture or one similar that will work. You then
hook the end of the speedometer cable to the spindle on the
rev counter as shown in the picture. I used a small piece
of rubber vacuum hose. Disconnect the two for now. The next
thing is to find a good section of highway that has clearly
marked mile markers that is safe to stop on. I used Hwy 49
not far from Lime Kiln on a Sunday morning. Pull the car
to stop at a mile marker and hook up the rev counter as shown.
Make sure the counter is set at O. Drive one mile to the
next marker and stop again. Write down the no. of revolutions
or disconnect the counter. The important thing here is that
the industry standard is 1000 revs. per mile. If your speedometer
is slow your number will be less than 1000 or vise versa.
Next you take this info to Commercial Speedometer in West
Sac. They will take this number and make up the proper over/underdrive
for your car. They did mine while I waited and I took it
home and installed and it worked just fine. I have 2 of these
rev counters so if you want to borrow one give me a call
and I will bring one to breakfast and you can use it. – Jack
If
your speedometer is mechanical and not electronic this should
work to make it accurate. When I had my 32 with the Hemi
in it the speedometer was way slow. Here is how I fixed it
First you have to disconnect the speedometer cable from the
back of the speedometer. You need a revcounter like the one
shown in the picture or one similar that will work. You then
hook the end of the speedometer cable to the spindle on the
rev counter as shown in the picture. I used a small piece
of rubber vacuum hose. Disconnect the two for now. The next
thing is to find a good section of highway that has clearly
marked mile markers that is safe to stop on. I used Hwy 49
not far from Lime Kiln on a Sunday morning. Pull the car
to stop at a mile marker and hook up the rev counter as shown.
Make sure the counter is set at O. Drive one mile to the
next marker and stop again. Write down the no. of revolutions
or disconnect the counter. The important thing here is that
the industry standard is 1000 revs. per mile. If your speedometer
is slow your number will be less than 1000 or vise versa.
Next you take this info to Commercial Speedometer in West
Sac. They will take this number and make up the proper over/underdrive
for your car. They did mine while I waited and I took it
home and installed and it worked just fine. I have 2 of these
rev counters so if you want to borrow one give me a call
and I will bring one to breakfast and you can use it. – Jack
