Hey all,

Getting ready to plumb a trans cooler in my 66 Dart. The -6 AN to 5/16 tube adaptor fittings (compression) say they are only good for 50 PSI. I think they are Fragola's.

I don't really want one of these popping off at the track, or anywhere for that matter, so I am curious if anyone knows the PSI that is in the transmission cooler lines for a 904. The trans does have a 9 inch convertor, reverse manual valve body, and a low gear set in it.

I am thinking double flaring the 5/16 tube to
37* and then using AN tube nuts and sleeves is safer ?

Thanks everyone !

Would that be less of a rating than a rubber hose and clamp? I think most cars have rubber tubing on most of them that are running the streets.

Even with raised line pressure the cooler circuit should be below 50 psi.

BTW, 37° lines aren't normally double-flared; single-flare lines run over 3000 psi in aircraft.

When building my 56 plymouth with 440 and 727..rather than trying to make or mold tubing I went to a hydraulic shop that makes hoses for construction equipment .. they gave me 12 feet of hose rated at 300 psi..don't think the trans builds up more than 40 psi. been in the car for 7 years now with no problem ,and was not that costly..just put hose fittings in the trans and ran the lines to the cooler and back.. EASY..