'79 carburetor and intake upgrade

[Vandrid]

So I am currently trying to remove my old carburetor, intake, and emissions crap. (since I am in Ohio no need for those) I have run into a bit of a snag. Looking through the older posts I have learned quite a bit but I can't seem to find the right size plug to plug the hole where the air injection check valve was. I have now tried an 18m 1.5, 16m 1.5, 3/8" plug and maybe a few others. nothing seems to fit. I also cannot seem to remove the rear valve nut, anyone know what size socket that is? can't seem to get it with my wrench

[scrapironchef]

Search "manifold plugs" on this site, there have been a couple of threads with links to suppliers.