As mentioned above, lube the threads and tighten the fittings while holding the part they are threading into.
Also, I've found most leaking fittings including brake lines need to be tightened, loosened and re-tightened about a have a dozen times to really seat them. You will notice the jam nuts threading in farther and farther each time you cycle the tightening process until they actually seat.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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