Go to montecarloss.com and ask the guys there about a guy in Canada named Conrad Lozier he makes replacement rear frame rails for the G-bodys just weld um in.
Then make it into a BRAKET CAR.
First pull the motor out and build a Hipo SBC the monte mounts will bolt right in.Get some nice headers etc......
Then make it a BRAKET CAR.
Have a nice tranny built w/ a good stall converter.
Then make it a BRAKET CAR.
If you don't have funds for wheel tubs and narrowing get some slicks,4.11-4.56 gears weld the spiders(did I suggest that??)get a posi and some traction bars.Or buy a whole GN 10 bolt rear w/ posi and change the gears.
Then make it BRAKET CAR.
Are ya getting my point??