I lead the rebirth of Swiss's 55 m62, we gave up on the vacuum governors (really 1 with 2 different controls), both the one on the power divider and the one on the distributor, we could not keep the engine running due to the rear one that had MANY vacuum leaks, so the lines to that were cut and caped, the front did NOTHING as governing the rpm, when the rpm got to TM rpm+200, there was NO governed affect, after some adjustment and fiddling, it was plain to see that we had more issues then worth trying to fix it, either froze up, just broke, vacuum leaks, ect., so we then disconnected and plugged the total governing system. This is the best thing we did to the old girl, she runs great. The governing is not really needed, If you can NOT drive and operate the rear USING the TACH and NEED the governor to operate, then you have NO business using the 62 in the first place. The 62 has been to the GA. rally twice, a good 2+ hrs each away, never a issue of over taching, setting the rear work between 750 and 1000 rpm with slight work rpm adjustments works great. The rebirth took place about 10 years ago, till now there has been NO issues due to governing system disconnection.
There ARE 3 solenoids on the 62, NONE for the vacuum system.
1-For horn
2-The master that is on the right frame rail next to the trans.
3-For the brake work lock
Call me if you want - 703-389-6705, Ron