I figured that Tracy uses 5/8" lines for his heat exchangers so that An 16 fitting should be more than adequate. I was also toying with having the radiator under the fuselage, and having lager lines than I needed would mean a lot more weight.

I'm going to mount my oil cooler inside the cowl. I'm going to make a custom cowl, omitting the cowl cheeks, but placing the spinner 44" in front of the firewall, instead of the stock 39". Attempt  a single air inlet for the rad, oil cooler, engine air intake. That may be a problem though.A cowl flap at the bottom rear of the firewall and put the exhaust under the airplane.

Brian Trubee
Redmond, Wa

Tracy uses two 5/8 lines as his two rads are in parallel as I recall.
The line pressure loss is a minority of the pressure loss in the system
considering the block and the radiator but why increase it by using small lines. 
I would use 1-1/4 ID lines minimum.

Paul Lamar
 
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