It was a challenge. Here is a list of steps. My coil was 6V and I am going to 12V. Plus the early Amazon's used a 3 bolt mount instead of two, so it didn't leave any options. The early P1800 used a 3 bolt mount, but I think the armored cable was too long.

1. Place the coil in a vise. Scribe a mark from the coil cap to base mount, so that it can be aligned later. Drill out the spot welds in the cap with an oversize drill. Then pry the cap off. A hammer and chisel/ pry bar may be necessary. Then cut the cable as close to the coil as possible. NOTE: Some people just cut the whole cap off. Might not be as easy.

2. Cut the top of coil off. Just cut off the red part. Don't cut into the metal of the coil housing.

3. The coil itself is bakelite/phenolic, filled with rubber, surrounding copper wound center core. Couple of options: Try and hammer out the cooper center core/manually pull out the cooper wire. Use a torch to melt the rubber out. Use a chisel to remove outer core after removing the center. You will have to be creative. Once the coil is out in pieces, you will notice metal shims inside the coil mount. Should be a couple of layers. I removed the first layer, filed the sharp edges and the new coil had a snug fit in the mount. NOTE: Not sure if a metal coil needs to be insulated from a metal mount. Might need to remove all shims and wrap new coil in electrical tape. Not sure. The hard part is done.

4. Decide if you wanted to retain the stock armored cable. If not, you could carefully cut or untwist the cable near the lock cylinder. Otherwise on the cap, drill a hole opposite 180* from where the armored cable enters the cap, or drill a hole into the coil mount itself 1" above the cap. Insert a rubber grommet and run the cable outside the coil mount and solder a new length of cable to it. From inside the car, it shouldn't be noticeable if it runs underneath the firewall insulation.

5. Depending on result from step #4 either cap the bottom of the coil mount. They sell black plastic I.D. caps at your local hardware for metal furniture. Or weld the original cap back to the base. Remember the mark that you made, so that you can align it. You may want to weld the holes that you drilled out first, before welding it to the base. BE very careful not to overheat the cap; we don't want to melt the insulation on the cable and cause a short. Epoxy might be a better and easier option. I haven't done this step yet myself.

6. Re-paint the coil mount and install. If you have to lengthen the armored cable (+), I recommend using similar gauge wire and soldering it. Apply Ox-guard to prevent oxidation and heat shrink the wire. If you retained the armored cable, it shouldn't be noticeable from inside that you modified it. Plus only the cap and cable stick out through the firewall insulation.

The best part is that the coil is still easy to access in the future. It should just pull out from the mount.

I used a Beru Blue coil. It was recommended by Hot-spark ignition because it is above 3 ohms. No voltage resistor is needed. If you have the early Bosch VJU 4 BL 33 distributor, the Hot Spark 3BOS4V2L kit fits, but you will need to slightly grind the vacuum advance pivot arm to clear the magnetic pick-up.

If you have any other questions just reply back. Hope that hopes. It just takes patience to accomplish.
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1959 Volvo Amazon