Thanks for the info, Larry. I think this is the route I'll take.If all you want is the Tees to gap into the engine coolant hoses, I bought ones from NAPA. Avoid the shiny all plastic ones (I think they were label for Fords) and buy the plastic ones that are reinforced with glass fibers.
They looked like these:
5/8 X 5/8 X 5/8 In. Plastic Heater Hose Tee NOE 6601672 | Buy Online - NAPA Auto Parts (napaonline.com)
They come in various sizes. I bought 5/8 x 3/8 x 5/8 and 3/4 x 3/8 x 3/4. I think the two heater hoses are slightly different sizes.