No, his points aren't valid. There are no benefits to having a pushrod 4-cylinder over a OHC 4-cylinder, there are benefits to having a pushrod V8 over an OHC V8. Thus his point, which he repeats often, is invalid.
GM's V6 pushrods aren't inadaquate because they are pushrods, they are inadequate because they've had relatively zero development dollars thrown at them compared to the HF series.
SMK repeatedly fails to understand that a DOHC and a pushrod of equal displacement will not have equal external dimensions. SMK fails to understand that you will not be able to fit a 6.3 litre DOHC V8 into the space that a 6.3 litre pushrod just barely fits in. Yet he continues to state this as true.
The CTS-V and Corvette do use a pushrod to smack around vehicles way out of their price class . This has been very publicly demonstrated.
Bringing the Koenigsegg into the discussion is just trolling. The Koenigsegg is over $500k. GM could outfit a Corvette with a Pratt & Whitney and still have it cost less. If the factory 638hp of the ZR-1 isn't fast enough for you, Lingenfelter will happily sell you an upgrade to about 680hp for roughly $3k.
So no.. it's not just differences of opinion. He's trolling by repeatedly posting information he knows to be false.
Everyone here is entitled to their own opinion.... however you're not entitled to your own facts.