Check out this performaxxstrings.com site. I know it's not the same as the Wilson gut, but it seems like most of their strings have the recommended tension between 50-65 lbs, with the exception of their XtraHigh Tension gut which is rated for up to 70 lbs.
So what I'm trying to say is that unless the Wilson gut you have specifically states that it can handle 70 lbs, I wouldn't risk trying it.
XtraHigh Tension Natural Gut
Our premium Natural Gut string designed specifically for players employing an extreme “Power game” with a VERY HARD, FAST Swing and VERY HIGH racket head speed and requiring higher string tensions. Traditionally, it was nearly impossible for players using this playing style to keep the ball on the court with natural gut. XtraHigh Tension (XHT) provides a much firmer string bed with a unique balance of power and control which allows these players the comfort, feel and long performance life of natural gut while using this electric style and higher string tensions. Excellent for use in hybrids with polyester.
Available in 1.25mm, and 1.30mm in both 20 & 40 foot lengths. Natural golden color
Last edited by volusiano; 12-28-2012 at 10:23 PM.