Yes.
Sort of. They will "fit", but the 600 pipes are smaller than the 700. You'll get more low end torque, but they will kill your top end HP.
I think it will.
I put a 99 FIII 700 engine in my 1997 Mach 1 chassis. I re-used all my original electronics, pipes, clutches. Just bolted on and go. Started second time I tried to start it. (first time, I used the 99 stator and it wouldn't fire up.. replaced with the one from my '97 and it ran perfectly.)
Easiest/best thing for you to do is find a set of 97 Mach 1 carbs/pipes/clutches to use. I believe all electronics are the same, but I would double check part numbers on the Doo microfishe to make sure.