I was inspired looking at the pictures Tippit posted of his modified Hoyt Pro Hunter. So here's the question. Is it possible to modify older bows to shoot FF strings - reinforce the limb tips?
The simple answer: possibly. I have heard that even if you beef up the limb tips sometimes the riser will break instead. I might suggest shooting an unwaxed endless loop string made from polyester if you want to boost performance without risking a vintage bow.
I have added tip overlays to older bows to shoot FF type strings.As long as the bow is in good shape with no signs of cracks or delamination.I have also known guys shoot FF low stretch string on older bows without any problems without reinforcing the tips.You'll get many different views and opinions on this subject.
I shoot 450+ on almost all my bows from selfbows, longbows, and older recurves. That modified Hoyt Pro Hunter has 450+ string. Do a search on Pow Wow, this has been debated a lot on both sides...tippit
PS: I shot that Hoyt Pro Hunter with B50 and 450+. It is soo much better and quieter with the 450+!
Some folks don't want to put low stretch strings on older bows. I've been using it on older bows for more than 10 years now without mishap I do pad the loops so the limb nocks are filled out nicely.
I use D97 on several vintage bows, some with overlays, some without. 10-12 strands loops padded to 16-18. Thousands of shots.