Yair . . .
fsmech.
What machines were they used that you worked in John?
It would be easier to list machines they were not used in.
In that era, before the bull@#*# started, a company could have its whole spread of machinery powered by the Jimmys. We had dredges scrapers, loaders, dozers, pumps and so on all powered by 71 series from two cylinder to sixteen cylinder . . . they were available in twenty four cylinder but I never saw one.
Trouble shooting, repair, and parts inventory were simplified. there were blokes around who could and did rebuild engines overnight.
In addition they were available in endless variations.
That 6-71 in your picture could be configured to run counter clockwise, laid over flat on the airbox side and I think the same on the blower side as well as being mounted with the crankshaft vertical and so doing away with the right angle gearbox on downhole pumps.
In their day they were a truly remarkable engine and even though they used a bit of fuel they were cheap and easy to rebuild and the "whole of life" numbers were pretty good . . . they made some folks a lot of money.
Cheers.