Overheating Issue

Send a pic of the inter-cooler and blower.
I always thought TIBs had water jacket turbos.
I learn stuff every day still.
Luv it.

If the concern is blocked dump can ports, it seems to me that the raw water hose going into the top of the can could be removed and a bore scope (endoscope) could be fished in there for a look around. They're under $15 on eBay all day long, and have lights built in. Mine works great and has a really good picture. The only difficulty is maintaining orientation, so it's best to fix it to a stiff wire,

Hope it helps you. Those cameras are incredible, especially for the price. Be aware that the OTG connector ones don't work with iPhones. They have BlueTooth ones for those, but the picture is not as good. I wish those had been available when I was doing a lot of electronics installations. Endoscopes and lipstick cameras didn't fall to under $200 until maybe 5 years ago. It's surprising how useful they can be.

I was just cruising thru an other web site. It reminded me again to ask you about soft raw water hoses on the low side of your raw water pump.
Run you hands along the whole hose run, if you can squeeze any part of the hose to the pump, it's bad.

I believe 170s would do you best. Replace the other engines thermostat also to help keep them matched.

On Covingtons I have had to make new tubes from glass tubes. I think you said yours were JTs. Maybe, maybe they still have some or fab up some glasd tubes also.
Call your Detroit shop, give them the serial and get the real thermo stats.
Heck, Detroit may have some tubes also. Depends on how many changes JT made and how was ordered from Detroit.
With the serial, a real Detroit shop can tell you everything and when it was delivered to JT.

Silver solder them up or patterns for glass tubes.

Fiberglass tubes.
I have been making them for years replacing old copper and steel lines.
I use pre-made elbows and hose connects but also can make one piece replacements.
Started with exhaust systems on re-powers years ago and moved to smaller tubes when needed.

The straight glass tubes, 45s and 90s are readily available from suppliers.
I use cloth and epoxies when ridged joints (or other angles) are required in one piece with the tube.
Oh, these tubes are usually rated for wet exhaust. I use them lots for gen-sets.

Still looking for pics of the inter-cooler and blower.