I had a hell of a time finding some to fit my macs. The 22 wont work. I took the no. 1 tube( the slip fit one with the air bung on it) to a machine shop and they said it has an odd pitch to the threads. I think they dont want u to plug it so thats why its such an odd size?? I had to run a 22 tap through em and they fit fine. He made em out of aluminum(i think) and they even match the coating on my header, looks damn good. I looked at every hardware store, autoparts store and tractor supply store with no luck. Take the headers to a machine shop and just have em make them. The guy wouldnt even charge me to make them he made so quick, but I slipped him a 20 spot anyway, might need something else one day. Stop looking around wasting time like I did and have them make em!! Good luck

 

You really should get the right size. You will have leaks. Also the teflon tape will melt. Use a copper sealant of some sort. Just giving you a heads up. 3/4 x16.