i don't see anything in the article that references the Stage 2 parts? i did a Ctrl+F for both "Stage II" and "Stage 2" and i didn't find anything that way either.
I also have heard that there may have been a few special heads cast and referred to as Stage II heads.
Stage 2 heads are designed so that they eliminate the exh port dogleg. there's a lot of material that has to come off of the exh side of the head in order to make this happen so *all* Stage 2 and up heads are header only. you can't attach an exh manifold if you want too.
i'm not sure if you could mill a standard head to get to a S2 type architecture, i'm thinking water jackets would probably be an issue.
Stage 2 cars were designed from the factory to use the Edelbrock B4B intake, TA has their own intakes.
this article has pics of a Stage 2 head in the raw ( notice the massive, round exhaust ports ) and pricing / casting numbers. TA heads don't have perfectly round ports.
there were only a couple of test mules built with these heads and about +150 head sets made by the factory. so pretty much everything Stg2 from back in the day is dealer or customer installed.
not much point in them beyond historical curiosity either. the original cast iron Stage 2 head is where TA got the design for their *aluminum* Stage 2 pieces. so, performance wise, you're much better off buying a new alum head from TA.
in TA terminology, "Street Eliminator" will fit an OEM cast intake while "Track Eliminator" requires a special intake.
Stage 1 will fit exh manifolds ( WHY? ), while Stage 2 and up require tube headers.