My conversion car uses the metric sized hoses from the oil tank to the cooler, with fittings to allow for changing the oil. Does anyone make a fitting that would allow one to simply unscrew a cap or plug instead of separating the 32 and 36mm fittings? After spilling oil during today's oil change, I think there must be another way. If the hoses were AN sized, a simple T fitting with a cap would do the truck, but i don't know if anyone makes a metrick T fitting.

No drain plug on the tank? Okay.

One option is to source an AN-NPT-AN tee, then install a Fumoto ball valve into the NPT center port. You may have to find a tee with female and male AN ends to splice into an existing hose connection. They're out there.
Click to view attachment

Sherwood

The connection point on a 914-6 is not on the oil tank, but rather by the trailing arms in between the two hoses. That's where my car has a fitting that both hoses attach to, and that's the one that I'd like to find an easy drain option like the pictured valves.

Since everyone else in the world but us uses metric fasteners, I'd be astonished if nobody made one.

Check with your local tractor supply. Caterpillar is evidently one of the largest users of metric fasteners on the planet. Failing that, check McMaster-Carr and then start Googling.

--DD