I would not waste my time w/a PG trans, you can swap in a TH350 trans, no change of driveshaft, crossmember.
You will get better acceleration everwhere.
If your engine is all stock, just to be cheap, you can use a 10" Chevy Vega converter that will give you a higher stall for cheap.
It's not that beefy, but for a stock engine not making that much power, it will work fine.
MBHD