A good source would be a late 60's early 70's NHRA / AHRA Rule book & Mandatory Safety Specs Per SEMA which were available to any racer and still are today.
By '69 - '70 most if not all multi-piece safety shields (non hydroformed especially) were outlawed by nearly all Major Sanctioning bodies.
Previous to that any cast or multiple piece steel weld ups
were outlawed (I think before the '68 Season).
I'm referring to NATIONAL EVENTS Where these Class Cars went through comprehensive inspections........
I'm sure smaller tracks / non sanctioned tracks passed nearly anything "modern" with a SEMA Tag, NHRA Tag.
SEMA Approved pieces changed multiple times throughout calendar years.
Note approval certification #'s & codes on current & older tags,,,, most aren't dated, but coded.
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Day Two Specialties /High Quality Muscle Car Parts.
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