When he started driving it.
https://www.allpar.com/threads/roy-clark-mopar-racer.216775/
From Weld wheels website
Founded in a Kansas City garage in 1967, WELD was the result of a relentless pursuit of speed, durability and safety. The company engineers and produces performance automotive wheels for professional racing, off-road and aftermarket vehicles. WELD wheels are designed and engineered in the USA
So, my info that it was the 80s may be wrong,, but they were not in use in 65. Roy's nickname was superpicker