champion radiator alluminum overflow tank

This is the tank I used, canton racing. not cheap.

http://www.summitracing.com/parts/CTR-80-200/?rtype=10

I used -6AN XRP fittings. The radiator was already threaded for the overflow, which was 1/8" NPT. I used an 1/8 NPT to -6AN adapter from the radiator to the bottom of the overflow tank. Same thing for the vent on the recovery tank. Because the tank was a 1/2' NPT, on the bottom, I had to use another adapter; 1/2"NPT to -6AN.