I tested a bunch of the fittings I have lying around to see what would fit. Of all I found only two that would not. One is the Koolance 90 degree rotary and the other was a 3/8 BPST fitting for a TC rad ;) LOL. I tried to get it in though.
The roundup:
http://img27.imageshack.us/img27/236...6530812241.jpg
Koolance fittings:
http://img187.imageshack.us/img187/3...6550816816.jpg
BP/DD fittings:
http://img398.imageshack.us/img398/3...6560826641.jpg
http://img196.imageshack.us/img196/7...6580837315.jpg
DD fittings:
http://img27.imageshack.us/img27/626...6590841809.jpg
Others (think one is an EK but not sure):
http://img263.imageshack.us/img263/4...6600846301.jpg

