the threads on the bolt don't do the sealing, it is the flanged area aroung the bulb that gets compressed between the square bolt and the seat in the bushing, you can't just use pipe fittings. As they arent pipe thread, I tried that and found out the one I was using was actually 5/8" NF bolt thread, There are at least 2 different size holes that were used in the heads, you just need to figure out which one you have. I have different heads that have it either way, I just can't recall off the top of my head which way it goes, but no matter they make adapters for either way. OH and by the way the reason the compression nut is square is so that it wiil fit through the square hole in the dash, that will eventually locate the gauge once you get all the tubing threaded through it. Jim Carter has any of the proper bushings you will need, there are most likely other vendors as well, he is just who I used.
Last edited by brokenhead; 05/28/2013 7:05 AM.
