Old thread but the 454 in my Georgie Boy runs at like 180-190 all day. The gauge reads high so I shot it with my IR gauge.
I run 20-25% coolant to water because as you said water is a better coolant and have a 190 t/stat.
I climbed from Phoenix to Flagstaff last summer in 100+ temps and while the needle climbed it never got over 220. I checked at the gas stop after the climb as we had more climbing to do to get into Joshua forest and I was concerned.
96 you'd have 8.1 Vortec w/Allison trans
One thing I noticed with the early-mid P-32 chassis RVs was the temp gauge on the dash differed in how the increments were shown on various model coaches. On my 1994 P-32 454 TBI the center of the temp gauge is 210 and boil was 260 (50 degree difference). The first gray bar to the right of 210 would end just before the first small red hash which I figure is ~240F. After that final red ash at (260F).
The following links are right after I did my coolant, T-stat (Delco 195F) and hoses (upper, lower and bypass) the IR reading is the temp right at the T-stat housing. The run was from the bottom of a hill (street) with a (1 mile) 6 percent climb at 80-85F.
Note the IR readings taken from the same spot on the T-stat housing with the doghouse up once stopped idling vs the dash gauge reading. Crazy eh?
Bottom of hill:
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Top of hill:
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What I found out was when doing the coolant I inadvertently bought 'concentrated coolant' (70/30) coolant vs water. Will run hotter. So after using distilled water I got the ratio down to approximately 55 percent distilled water vs 45 percent coolant. After that the needle behaved better but still not accurate to say the least. The dash temp gauge on those era RVs is not very accurate at all. They read often times on the high side by as much as 20-40+F degrees. Most often noted on warm days.
The normal operating range for those era chassis was anywhere from 195 - 240F. That comes from a GM tech I know that worked on them for years back then. He told me folks used to complain often about the dash gauge wildly going up-down.
On the flats the dash temp gauge will hang at 210 or slightly to the right (half needle width) when at cruise speed of ~60mph on 80+F degree day. The clutch fan cycles more often the warmer the ambient temp is. On a hot day say 90-100+F at cruise speed (60mph)the temp will be anywhere from 212-218. That is what shows on my ALDL phone app I have which pulls the temp from the ECM which gets the temp from the CTS on front of intake manifold.
GM ran em hot in that era due to smog nazis.