As the old original generator was tired and did not charge sufficiently, I had to recharge the battery from time to time to be able to start the old lady and the headlights and rear lights were dim, I went ahead and purchased a renovated 63 amp alternator from 1973 Cadillac with internal chargingrelay. Supplier TA Motor Luleå, Sweden.
And by the way, in the US a 63 amp alternator can be found at Partsgeek .
The switch to this alternator was quite straight forward and for details see below photos with descriptions. Now the alternator charges from low idle with 14,2-14,7V, and we´ll see how the durability over the summer cruises are.