"...didn’t see any RA2 cars in that 1998-2015 PSMCD era."
In more recent years, I think the RA2 Birds are the quickest Pontiacs in Pure Stock type racing.
I don't know if that's just because nobody has done a real serious pure stock RA4 Bird build, but some have done the RA2 Birds.
Again, the scarcity & price of the RA4 heads may be a factor.
Going quick, under pure stock type rules, is not easy. So, to do it, requires people who know what they're doing, & have the time & money to put into the project. Also must have a real desire to wring everything they can out of the combination. There are just not that many qualified guys around who have all these things going for them, IMO.
A Pontiac name I've seen more than any other, connected with pure stock type racing, is Dan Jensen.
https://www.motortrend.com/how-to/hp...ol-pt1-engine/