The NHRA introduced the Pro Stock class in 1970.
Pro Stock emerged from production-based Super Stock racing, where highly modified showroom-derived cars had become increasingly popular. The new class used more liberal technical rules and, crucially, removed the handicapped starts associated with much of Super Stock competition. Cars therefore raced heads-up against one another.
The early formula favored large-displacement V8 engines, and Chrysler Hemi-powered cars won the first two Pro Stock world championships. Ronnie Sox won the inaugural 1970 title, followed by Mike Fons in 1971. The NHRA later adjusted the rules to give smaller-displacement V8s and compact cars a more competitive opportunity.
Pro Stock is often called an “all-motor” class because forced induction and nitrous oxide are not part of its traditional formula. It is also distinct from Pro Stock Motorcycle, which the NHRA added in 1987. The 1970 launch makes Pro Stock younger than Top Fuel and Funny Car, introduced in 1965 and 1966 respectively.