For what it's worth, I saw an old PT-445 for sale on facebook marketplace recently. It had an old ford industrial gas engine that looked to be original.
I have found PB Blaster to be a mediocre penetrating fluid. I use it out of convenience, but for tough stuff I use a mixture of ATF and acetone instead. It certainly outperforms PB Blaster. At work I use Kroil. It is also superior to PB Blaster but isn't cheap.