[X-FID]

In had a four cylinder L-head style engine (where the valves are in the block), which could operate at 4000 revolutions per minute for 100 hours straight.

I'm no gear-head, but these are some awesome specs for a 4 banger, of course that may have been the upper limit, but it would still have to be screaming for 100 straight hrs, with or without the transmission load that's quite impressive.

[snippy_about_it]

screaming for 100 straight hrs

I wonder how often they required maintenance.

LOL. At least those were the days when a vehicle needed maintenance you could actually get to the parts to do it yourself.