If he Z'd it, it'd probably be best to cut the front about where that hole is (where the stick is .... uh, sticking out.) And then another cut at the rear. Just replace all that with rec. tube. It'd have to be widened somewhere, but you could decide where. A lot easier than trying to cut and use what's there.
And if you can find a rear steer R&P that'll fit a S10, you could stretch the front wheels forward and help the proportions out.