How far to forward is it?

Look at this tech tip from my '37.

http://www.stovebolt.com/techtips/driveline/swaybar/index.html

I used the same sway bar you have which was really long for this chassis. I went over the axle and mounted it behind. It works just the same way and gave me the clearance I needed to mount it with bolt on brackets. There is no danger of it ever getting hit by the axle or frame and if it does, you did something very wrong and that would be the least of your worries.

Joe

1937 Chevrolet Inline-powered Streetrod