I had to use Teflon tape on the pipe threads due to worn threads, just keep the tape back from the first three or so threads, if your using anything on flare or compression fittings that means the flare or compression fittings need to be re-made.

1957 Chevrolet 5700 LCF 283 SM420 2 speed rear, 1955 IH 300U T/A, 1978 Corvette 350 auto, 1978 Yamaha DT175, 1999 Harley Davidson Softail Fat Boy