I am taking up Sean's invitation, and moving a Huntercombe-related exchange over from the '2 par fives' thread.
It could also be that in the change of handicapping system, the 16th became a par 4. Its hard to believe it remained a par 5 for its entire existence. Otherwise, why squeeze out more yards to that 475ish mark?
Yes, I think Huntercombe was considered very long in its day. I have seen some old yardages and few stand out as remarkably changed. Maybe you would care to offer your opinion #s 2, 3, 5 and 14. I don't want to overly hijack this thread so reply using the Huntercombe link.'
To answer as fully as I can, taking a lot of material from both John Moreton's centenary history (2001) and the earlier (1983) booklet by John Adams which, very usefully, contains a plan (reprinted from Golf Illustrated) of the near-original layout of August 1901,
the 2nd (original 7th, at 490 yards) was originally played much closer to the current 5th fairway, and doglegged round to a green some way above the present location: shortly after the opening, the field on which much of the 2nd now plays was obtained by the club, and one of the best bunkerless holes in golf gradually emerged. The green originally sloped markedly away from the player, but by 1904 it had been flattened and built up at the rear (as now). How this original hole could have been nearly 100 yards longer than the current 2nd is not, however, clear, and isn't accounted for simply by improvements in measurement techniques.
the 3rd (original 8th, at 456 yards) was likewise at least 80 yards longer, and the 1901 plan does suggest a tee much closer to the 2nd green, rather than the current walk through the bushes, and that would certainly account for much of the divergence (in addition to suggesting a truly heroic hole of c450 yards, given the nature of the green)
the 5th (original 10th, at 496 yards) tee was likewise further back, beside the 4th green, and it looks from the plan as if the 5th green itself was further on, almost behind what is now the 1st tee (I hope this is all making sense, and apologies to the non-Huntercombe-familiar): that would account for the 90-yard discrepancy in yardage
the 14th (original 1st, at 473 yards) may have played to a green a little further on from the current site (it's clear from the August 1901 plan that at no time was the original 1st tee ever across the Oxford-Henley road, close to the original clubhouse) and that seems the only explanation for the additional 40 yards.
My only other piece of evidence is a scorecard of my father's from ( would guess) the late 1940s, and that gives the current 14th (then 439 yards), 16th (443), 6th (520), 8th (438), and 12th (419) all as bogey five, and an overall bogey of 73.
I should perhaps state that by Huntercombe standards I am a relative newbie, having only been a member for about 20 years, although my uncle Neill was secretary there during the 1970s, and the family connection goes back, as mentioned, quite a way.
Hope this helps, anyway. Rye has famously contracted over the years, and I wonder what other 'category one' courses have actively shrunk in the century or so since their foundation? Luffenham, which lost a trio of holes during WW2, might be a contender, and I am sure many GCAers can think of others: Rhyl, where the Welsh Championship was played immediately before WW2, and which lost half its course, is perhaps the most extreme example (without ceasing to exist altogether) that I know of personally.