76 K100 AMP ,OIL ETC gauge SIZE

Pyro is not as small as the oil pressure, amp gauges in my 83 K100C….

 

Pretty sure 2",, 2 1/16" hole, was the standard for most small gauges. I have seen small pyrometers, but they are hard to read. Those KW pyrometers were used for years and should be no trouble finding a NOS one.

 

The smaller gauges are 2" holes but most of those gauges have a Indexing mark on them so you might have to file a slot in your hole for the mark
As @OLDSKOOLERnWV stated most of the pyro gauges are 3" holes which is the size of the bigger gauge your refering to

 

If you are using a hole saw to make holes in the dash panel for a gauge remove the drill bit from the hole saw arbour and replace it with a length of 1/4" rod. Drill a 1/4" hole where you want the gauge and finish it with the hole saw. you will get a better finished cut. Leaving the drill in the hole saw arbour as you bore the hole the 1/4" bit make the 1/4" hole bigger and the hole saw "wanders" a bit making a rough hole.

 

Isspro does make 2” pyros that have same faces as the 3”ones. They offer choice of both black bezel or chrome. But because they are not as common they are around $100 more than the standard 3”.

 

The best source for the older Sterwert-Werner gauges is Summit Racing online. They have the whole S-W catalog and all the styles and types. Mechanical and electric. “Deluxe” is the style that KW and Pete used.

 

I've got a 2" Isspro with the chrome bezel that I just took out of my 359.. if you have a use for it your welcome to it.. It works fine I took it out because I had a hard time reading it at a glance and I'am switching motors and I need to keep a close watch on my ET. plus I wanted a fuel pressue gauge in its place because that is going to be a issue now also