Conversions & Hybrids - quick q - intake manifold plug on edelbrock intake 7118

Would anyone happen to know what size plug is needed for the edelbrock performer dual plane intake manifold? I thought it was 3/8" NPT but that's a little too big.

http://sites.google.com/site/zigzautonotes/images/LS1_edelbrock_performer_intake_plug.jpg

Thanks guys

nm, i'm a dumbass. it is 3/8" npt. i had a 1/2" in my hand and thought it was 3/8. D'OH