looks like u use mustang cobra shafts with cosworth ends at the wheels end, maybe it would be a little costly by the time its all done, but it would be very strong, here is the cobra shafts next to standard cosworth ones, i'm using the 8.8 and cobra shafts in my kit so took a photo of the difference compared to cosworth, photo doesn't show it very good, but the cobra are about 2x the thickness of the cosworth shaft

cobra is the new shaft and the cosworth is the old shaft