Oil/Transmission Cooler Fittings

Hey guys, I’ve been striking out big time trying to find fittings for this stacked fin cooler I’m trying to use as a heater/heat recovery in my THOW.

I’m trying to get it to 3/4” barb so I can connect high temp silicone hose coming off a small generator exhaust.

I know it is AN sized (Army Navy) and pretty certain it is a 37 degree seat/seal angle.

I think it was a 1/2” Flare fitting that threaded in correctly (may have been 3/4”… but I’ve tried so many things, I forget), but I know they are 45 degree angles, so it would never seal.

I ordered and returned an -10 AN, but it was too big. I ordered something else and I was too small. Looking up the make and product number does me know good and most products I see online don’t have measurements on the diagrams. Seriously flustered at this point.

I’ve made a (concentric pipe) heat exchanger for water that’s gonna pull a lot of the heat out of the exhaust initially, but would like to pull the rest out through this radiator to heat space/air with a fan inside my tiny…. but I need a true/correct fitting to keep the exhaust sealed inside.

here’s some picts…

Any help appreciated

 

Side, but related question… has anyone added some sort of a heat exchanger off their coolant system to heat water say for overlanding when you’re driving to use later?