I scrounged all over for some specific info on the size plug that I'd need since I'm putting some EGR heads on a non-egr car. Some said 16.5x1.5 on one and 19x1.5 on another. Well, after ordering the 16x1.5 from Fastenal and seeing that they were way too small, I decided to just use an old EGR tube to make a couple of plugs.
I cut the tube ends with a sawzall and put one in the vice. I chose a 5/8-18 thread since I couldn't really find a pipe tap that would work easily. I'm guessing that a 3/8 NPT tap might have worked, but I can't confirm that. I picked up a 9/16 drill bit to go with the tap. It calls for something like a 37/64 drill bit, but good luck finding that. I picked a 9/16 since it was close.
I started some threads after drilling and added pipe dope to the inner most threads on the plug and blue loctite on the outermost threads. It doesn't look to bad and it's solid.
Since I'm using EJ25 EGR heads on a non-egr car, I didn't have to worry about a cover plate for the intake.
