A '66-'67 Chevy II isn't heavy at all,full weight around 2800ish with a aluminum head small block,gutted even lighter. Gotta remember,the Chevy II was Chevys "compact" (besides the Corvair) car back then-they even offered a 4cyl engine in them,going into the 68-72 era cars.
Leaf springs in itself aren't a huge handicap these days,lots of guys going 9's on leaf springs and Cal-Trac bars. Just look at NHRA stockers,leaving with the front wheels '3 in the air and dipping in the 9's on like an 8 or 9 inch slick.
I was at the Hot Rod Pump Gas Drags in '04 with a buddy who was competing with his 528 Hemi '65 Coronet. One car there was a unassuming white '64 Chevy II from Cali owned by Jim Henn (RIP). The guy was a Toyota NASCAR engine builder. Steel wheels with tiny DOT tires,column shift,stock mismatched bench seats,full 2 1/4 exhaust ect. When he drove into Comp cams parking lot,it looked and sounded like a 13-14 sec car-he ended up running 9.70s @140 plus. He was running a B&M mini blower and nitrous. Sick car. I wish I could find a pic.
Now,whether this particular car goes 9's remains to be seen.... /ubbthreads/images/graemlins/dunno.gif