WANT '71 280SEL,
I use a meat thermometer I got at a truck stop to check vent temps. Look in a Pilot or Loves in the trucker parts shelves. They are a few bucks and work great. It has a clip like on a ball point pen and a small dial that indicated the temp. Really helps to determine what you AC is doing.
I can't help much on the pressures for 134a. The original dryers may not work as well wth 134a. If it is indeed an "original" R-12 type.
Good Luck to all!
