Wondering because i installed a weber its going great. Today i decided to ditch the egr and tube and install a plug supplied in the kit for the manifold. Well 1 wtf they give an aluminum plug idk... 2 it screwed in fine by hand to start it a little... Start tightening it and it got real tight and i wasnt even halfway down the threads on the plug.... I know it was no where near bottomed out!!!! So i take it out and yea threads gone up to maybe first 3 rows. Well i know that pos alum plug didnt ruin that steel manifold. But looks like i got the molten alum out of the threads of one spot but another spot has some and i cant seems to scrape it out. I dont want to take the manifold off. Im going to try and get a tap but need the thread size and pitch. Thanks all! Its weird only 2 spots have the aluminum in the threads. Maybe a 1/4" long spot each. Like as if it wasnt even screwing all the way around.