I updated my rFactor2 to build 770. Changed the executables to 64 bit but the program is still installed in Windows 7 32 bit application folder. Will that have any affect on performance? Thanks.
It won't have any effect. Although it is generally recommended with games - especially those which are moddable - that you don't install them in Program Files due to the restrictions Windows puts (or at least tries to) on activity in this directory. I install all my games under C:\GAMES (helps find game folders anyway, not being mixed up with other programs...) Like I said though, there won't be any effect on performance.
You will have no problems, best bet is not to install in any Programs folder. That way you are always assured of having control.