Grant,
I wish I could answer that question. I'm not able to find it in any of my books. I did a search on this site under "temperature gauge" and found lots of postings, and it seems to be a universal problem. I'll do some more research. I have had better luck at Pick Your Part for this type item than through most parts suppliers.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine