Originally Posted by
RCMoeur
My opinion is the Pro Mk IV is a thoroughbred, not a pack horse. Yes, it has head and seat tube angles that would be considered "touring" these days, but I'd be surprised if the original owner could get pannier heel clearance with those short chainstays plus the absence of eyelets on the dropouts meant the rack attachment had to have been somewhat improvised. My Pro was set up as a compact double even before compact doubles were cool, using a period-correct 110 BCD crank. That offers saner gearing but still looks "clean". Best to you in the refurbishment.
The Professional features upright 74-degree angles in this vintage as I recall, same as the Competition of the same year.
Now the Super Course has more like gravel-bike or hybrid 71/73 angles that give the bike it's particular character, making it a most calm descender.
The trick to running a triple on the Pro is not ending up with excess chainline, meaning the shortest spindle possible, then making a front derailer pull inward far enough for a robust downshift to the granny.