I'm in the process of upgrading my transmission cooler to a B&M 70274...i already have braided lines so i grabbed a couple of Aeroquip -6 AN to 1/2 NPT fittings...my question is are these supposed to screw all the way in and bottom out? After only about five or so threads it slowly got tighter, but i didnt want to strip it so i stopped...maybe has 5 ft lbs on it now

 

You're good, I have that same cooler on my 99 build and it's NPT which are tapered threads so it will get tighter as you tighten so do not try to bottom them out.

 

Cool man, i found a video that explained NPT threads should be hand tightened then 1.5 to 3 turns and its good.....i loosened them, then ended up at 1.5 turns past hand tight and it felt rock solid

 

They are fine

 

NPT is tapered thread and have no place in modern society. why it is so widely used when there are far better options is beyond me.

 

You can weld around the fitting if leaking is a concern. I did it on my cooler.

 

I've used NPT -6 fitting on the cooler lines into the stacked plate cooler a number of times. Zero issues.