Trans line ideas

Currently plumbing one in my Dart, with a plate-type cooler like StrokerScamp's, but smaller. My cooler has 5/16" tube stubs, so must use at least short hose, but will mostly run 5/16" steel tube. My factory tubes were cut in the middle w/ short pieces of rubber hose (why?), so I am running all new tubes (couldn't find pre-made for 65).

I put one in my Newport years ago, but a smaller tube & fin type. That also had just barbed fittings, so had to use a little hose. I bypassed the radiator cooler there and I found the return tube (727 rear fitting) runs cool (~120 F, can hold my fingers on it). Therefore, I don't seem to need the radiator cooler. I got another plate-type cooler, which is bigger and better, so will switch to that soon. Both were ~$10 at a swap meet.

Re using rubber hoses. Smart to eliminate as much as possible. However, my 2 Mopar minivans use rubber all the way from the tranny to radiator. Had a few leaks, but because the factory used cheap spring clamps. I think the return on Torqueflites dumps into the pan, so shouldn't be much back-pressure on the cooler and hoses. Next time I have one open, I'll probe w/ a wire to verify.

Re using or bypassing the radiator water-to-oil cooler, most manufacturers recommend using. However, that risks getting trans oil in the radiator, or worse, water in the tranny. Some cars, like my Mercedes, have a separate trans radiator. The factory probably did the radiator cooler because cheaper. I am still deciding for my Dart.