That's an afc adjustment. Try fiddling with It a bit. Should be a bit cooler around that rpm. What's your timing at?

Your gearing definitely could be better though. I think that's a fair part of it probably close to 100f.

Stock timing for a 96 so I think its around 14 or something like that.

I think it's lower then that. But even still Id suggest going up a bit to at least 16 or so, your studded and depending on your weather conditions you could go as high as around 20 and run it in winter. It will improve power, mileage, egts. You won't make much power at low timing. If it runs weird with timing you must have other issues. The only thing that should change is the sound and that's more around the 20 mark.

Depending on where you live and how cold it has to start, I wouldn't go above 16...

Just me

I live in winnipeg Manitoba Canada. There is no where in America other than Alaska that gets colder then here. Buddies truck runs 20.5 degrees of timing. If you plug it in at night and have a grid heater you will be fine. If you've taken the grid heater out then Ya it will have Trouble starting.

I live in Prince Albert, Saskatchewan, Canada.
I feel your pain. (How but this year though hey?!)
Fun fact: I'll be in Winnipeg for the 2 jets games at the end of december 😃.

I know a HD tech who runs his own shop in Saskatoon and worked at Cummins western Canada for quite a while. They would set the 12v at 15-17. More than that and guys started complaining.
The independent shop I get a fair few parts from here in P.A. says the same.

If I had something like a webasto/Espar I'd say go hard.

What would you guys think of a mishmoto intercooler for lowering egts.

I want to do delivery valves but won't happen with this level of egts now.

Intercooler will help. But timing will likely help more. Plus help in so many other ways. You have all those parts + stock timing. It's not really how it's done. At the very least bump the timing a bit. To like 16 or 17. It's basically free hp. We made almost 60hp just from a 3 degree timing change and a set of sac injectors vs vco. Your industrial injectors might not be helping either, they are likely vco. And like most industrial parts they are low buck/ technology with a price tag. Oh your canadian slim! Well you know the pain then. I can see my buddy having some issues leaving it not plugged in but plugged in with the heater I think the 20.5 will work out all right.