I haven't figured out what PHS means yet.
I did find the build sheet over the gas tank when I changed the frame, it was rusted out, bent and cracked. It has a 350 2 barrel and had the TH350. It was stock and complete when I got it, except for the missing sheetmetal.
I swapped in a 200-4R for overdrive, and ditched the points distributor for an HEI from a '78 Grand Prix. I also had to put in a new gas tank and redid all the brake lines. I'm about to do a 4 barrel swap also, might even start that today.