I think it is just more of a feel good thing to do, or like in my case I did not have ramps, nor a slight slope/hill nearby, and I did not want to drive around with air possibly in the system, while trying to find a slight slope/hill to park on, so that is partially the reason I drilled the hole, the other reason was I kind of like the idea of a small stream of coolant constantly circulating in the system.
I guess I could have put my jack in the front middle of the car, and raised it up a bit, but I figured I'd try the hole, because I went with a Stant Superstat thermostat, and did not see the little hole that has a small ball/check valve or whatever you'd call it on it, the OE AC Delcos should have them, of course I threw mine away before verifying it had one or not.
I don't think even that is necessary, as the way the thermostat opens when hot is essentially the same thing as the tiny ball/check valve opening when you squeeze on the radiator hose.

This baby makes bleeding easy......

Nice, have never seen that till now, thanks for sharing that Gus!

I think I am going to get a new Delco rad cap.
I noticed last night after a good hot parked run up reached 212 F & then cooled for 10 hours the top rad hose was sucked inwards a bit like a vacuum..hmm...any thoughts?
The car temps on average runs on hwy below the 195F.
City temps stop & go average 192-200F (no A/C on)
The thermostat that I have in there is a Prestone Failsafe Ultra Life.
No I did not drill it William as I felt in winter, I like the real quick warm ups.

The hole really does not effect the winter warmups, not that I have noticed anyway, it seems to have hot heat ready within a couple of minutes like always.
I'll try to time it next winter to see how long it takes to put out warm heat, I want to say like 2-3 minutes, but I am just guessing because I have never really timed it, I know a minute or so after I reach closed loop the heat is coming out pretty warm.

Ya Thanks William I know the PA heats up well in winter/quickly!
I think I am on the right track with new rad Cap....Just got back from Dealer...

Will see if it pressurizes/vents better now (15psi this cap is) stock for PA according to dealer.

The new rad cap pictured above did the trick. Now it is pressurizing properly.
It is also a lot easier to remove the new cap because it has the 2 ear grips on outside of cap.
It would appear the old rad cap was the original. Lasted 17 years.
Was worn and leaking slightly I discovered, from rubber seal.
Ya this old cap is now retired LOL!

Glad to hear that fixed your pressurization issue, I replaced my cap back in the end of 2011, I was going to go with an AC Delco one, but went with a Stant 10331 Lev-R-Vent Radiator Cap, the Lev-R-Vent was not really needed, but once when younger I thought my Moms radiator had cooled enough, turns out it was hotter than normal as she had more water in it than coolant, and it sprayed me in my face, and burnt my cheek and neck a bit, I know I'll never open one that is even remotely warm ever again, but still I got it to make me feel a little safer.




I may replace it before too long, as I have heard that the drop-center type thermostats can cause sealing problems over time, I'll replace it with a spring-center type thermostat that is supposed to seal better, and last longer.