I had an opportunity to speak with an older gentleman who was a lifelong Pontiac mechanic back in the hay day. I specifically asked him about these cars and if they ran hot out of the box when new.

He simply said NO! In fact, he said that these "hot" issues didn't come about until people started playing with these cars. Things such as headers, switching carbs, cams, rads, intakes and the list goes on. He said every old Pontiac that came in the shop with running hot issues, was ALWAYS modified in some way.

I can only speak from my own personal experience on this topic. Once I had rebuilt my 68 Bird 400/4-speed pushing 405hp at the rear wheels, back to OEM specs with ALL of the above mentioned parts and pieces, I went from 7 YEARS of running hot to NEVER running hot in the matter of one day. The very day I completed installing all the OEM/stock/original parts and pieces. The last piece of the puzzle for me was the 19.5" 7-blade clutch fan.

The day I installed that fan (every other OEM part was in place) ALL of my hot issues were gone forever! After that, I would drive the Bird on Daytona Beach in 98* temps at 5mph for a 7-10 mile stretch on the beach and NEVER once ran over 190* and NEVER ONCE boiled over and never having a recovery bottle as well. This was a car that for 7 years could NOT sit through a redlight for two cycles without overheating!

Going back to the basics will solve hot issues on these old Pontiacs. However, you must find and install ALL of these parts as they rely on one another to make a fully functional cooling system...