String and Brace

[Bigjackfish]

I have a 1962 Bear Polar 40lb 66'' recommended brace ht is 7 1/4-8 1/4 .I use a 63'' string with a brace ht of 7 3/4 seems to work ok .Some one suggested I run a brace ht of 8 3/4 to get the thump out of the bow .It does have a little thump at the shot,will this have any adverse effect on an old bow like this one .A string length of 61 1/2 was suggested to get the bow up to the 8 3/4 brace ht any input welcome to what would be best for the bow first and performance second.Thanks for any help.

[Orion]

Does the thump bother you?  Are you getting good arrow flight at the current brace height.  You're right in the middle of the recommended brace height.  If it's working for you, why change it?  Increasing the brace height will reduce performance.  Likely will have no improved affect re bow longevity.