Well driven no doubt. Phil..
Naaaah-all Volvo drivers are to be presumed cheaters and bottom feeding vermin incapable of any of the kind of integrity, skill, or the intelligence that a real winner requires. They are constitutionally incapable of ever doing the right thing and are never to be believed.
(ps: only the 71 142E <70/71 1800E also>had the great cam with 5deg addtl duration on both lobes. It may have had .010"? more lift as well. Of course the used cam was perfect-they never had a wear problem! I degreed the best original cam I found @ever 5deg and archived the info as well as in graphing it. I did this with BHP cam and aftermarket D (I think that was it-been 20yrs) or whatever was the B20E cam. All that went to Brumstead and co when everything was sold to people in Ithica. Point is, they were VERY close to one another as in legal.
I've run BHP springs, IPD B20 stock, and factory B20 springs. None were near coil bound when installed ht was legal and all needed regular replacement depending on how much you stretched the shift point. And I would be amazed to the improvement at WGI that you experienced)
PPS: I really doubt that any mentioned /volvo drivers are cheaters. Also, except for a notable overperformer @WGI, I can't think of any notable Volvo guys that are more than gray.