[Peter Serio]

This is from a Kent Moore tester:

Note that this chart does not even list the early (2nd Gen.) trans am temperature increments. (210 at the 1/2 scale.)

I stand corrected; my point however it happened is that the "normal" underhood temperatures increased by the added EGR valve and then again even more by the addition of the catalytic converter.

At least that is my theory on the center line; painted # going from 210 up to 220 degrees on the 1970s Pontiacs.

Same deal on the big end 250 to 260.

After 1973 I do not believe that those early gauges were available to order from GM anyway. Those temp gauge 100-210-250 markings may have only come on cars "as built." If you needed a replacement gauge, say in 1978, for a 1972 Trans Am. The original part # for the early cars was superseded by the 100-220-260 version.

And all that the aftermarket sells today is the 100-220-260 version.


Just FYI, photo posted here was automatically reduced in file size to the point where it looks blurry. My original jpeg is not.
I have the original; and it is big enough that it will print well enough to read, probably not from here.
If you need to print it out just PM me with your EM address and I will EM you the big file size!