I agree with glassphisheye. I have a 150mm Sherman (from an old, busted-up frame) on mine and it needs more. The geometry is a bit off, even in 6" setting on the frame. I'm gonna put a Marz. 66 on over the winter and that should do the trick. Definitely go with at least 170mm.
[SIZE=4]SEEK THE GNARL, LEST IT FIND YOU FIRST.[/SIZE]