This one comes under a couple of "headings". First, the Pontiac OHC 427 was "still-born". It made outrageous amounts of HP on a dyno, and was promptly "axed". That's the engine that appears in Hot Rod.
The M/T "hemis" and OHC engines were a bit different. Mickey Thompson's company actually made the heads, cams and drive pieces for the cams, not Pontiac. They were a "flash in the pan" as far as competition was concerned. NHRA outlawed them immediately (not "production"). NASCAR never even LOOKED at them...
As for building one today, why? GM and the aftermarket "world" have proven beyond doubt, pushrod engines are every bit as capable as OHC engines. The LS series is the example. The Ford and Mope OHC engines need a blower to make anywhere NEAR the power LSx makes. Even the modern Mope "Hemi" (in name only, as the chambers are NOT hemispherical) needs a blower to keep pace.
I suppose if one was to win the lottery and WANT to create the monster, go for it! Just be prepared to get beat by a more conventional approach.
One of the lessons "learned" by Ford with the SOHC 427 was the expense doesn't justify the results. And that's dealing with an engine that totally dominated every form of racing it was "legal" in for the short period parts were available. They abandoned it because was just too expensive to produce and maintain.
Fun to discuss, though... (:-