Chevrolet, Mopar, and Toyota are racing Nascar with engine families that never appeared in a production car.
I didn't check on ford.
The current Chevrolet is the R07, it replaced the SB 2.2, which replaced the last production based small block, the 18 degree version (production heads have a 23 degree valve angle, not 18 degrees). The SB 2 and SB 2.2 were both based on the original production small block, the heads will bolt on a production small block. The R07 is all new, although it shares some dimensions. They used the 18 degree version of the original 23 degree production engine in the nineties, they used 23 degree engines before that, same as production.
Toyota has never had an over head valve cam in block production V8 in the 350cid range.
Mopar has pulled out, but their engine was distant kin to the old 340/360 W2 engines. At least the last one I saw 3-4 years or so ago was.
Ford was using a "blend" of the Cleveland and Windsor engines that was not a production engine ever, as far back as the very early eighties. They were using a Cleveland head, on a Windsor block (with Cleveland main bores) that was supposed to be "Australian".