No, the adapter ring for a PG is basically circular, and only about 2 inches thick. The bellhousing of a PG trans is nothing like the shape of a 350. The Chevy-pattern 350 bellhousing would be a direct fit to the 3rd-generation inlines like the 194, 230, 250, and 292, all the V8's, and some of the V6's. It will also bolt onto the "Iron Duke" 4 cylinders like the Mercruiser or the 4-cylinder Chevy II engines.
Jerry