After mixing and matching used speedo parts for years, I got too old and stiff for another round of speedo removal so I bought an after market one for one last go at it. It has worked well for a decade or so. To remove the speedo I used the 52 Carl method and pulled the glove box and then the speaker grill. Then to get the choke cable loose, I had a 9/16 combination wrench I cut in two and used the open end part to nibble away at the cable-retaining nut. I made the tool when working under the dash but with the grill out you may not need that. Once the choke cable is out of the way I used my 1/4" drive ratchet to remove the speedo retaining nuts. Remove the lights and the drive cable and you're home free. A little penetrating oil on the various nuts makes the job easier.
Previously, I had checked the speedo accuracy on the mix/match speedos with a short length of flexible cable hooked up to my drill press. You have to calculate what your drill press RPM is against 1,000 revs per mile, which is 60 MPH. One of my drill press speeds was equivalent to 37 MPH. I learned this trick from working on Smiths magnetic motorcycle speedos. I didn't do this on the new one. My bad. Now with the 4.57 gear ratio instead of the 5.13 the speedo is accurate but the odometer is off. Sigh. Having changed gear ratios, tire size and with the brownie transmission it gets complicated. So eventually, if I live that long, I'll calculate the revs per mile on the brownie's speedo drive, get a ratio adapter, a looong cable, pull the speedo and re calibrate it. Meanwhile I've learned to drive by the tach.
