Re: 1959-63 QD’s Opinions?

[Don]

The smaller gearcase is definitely an issue, and good driveshafts are definitely scarce. Later model 1960 versions picked up the larger wrist pins and wrist pin bearings though…So, you definitely want to check for wrist pin slop on the 56-60 models.
So, I guess I would sum up the issues this way:
55-57 models had the more robust larger gearcase, but also suffered from premature wrist pin wear.
58- mid 60s models had the delicate smaller gearcase and the small wrist pins
later 60s -63 models had heavier wrist pins/bearings along with thermostatically controlled cooling systems, but these engines used the delicate small gearcase
One further note. Older powerheads with the small wrist pins can be updated by changing the pistons/wrist pins/bearings.
The small/large gearcases can not be interchanged though, the midsections are completely different.
Regardless of these serious flaws, I love the way these engines run and the amount of power they develop. So, I would surely purchase those engines for the right price after doing some basic investigation….Check for wrist pin slop, then drain the gearcases….
Unfortunately, you may have to combine the best parts of both engines to get one good daily runner. Again, good new/used driveshafts for the small gearcase models are tough to find.