ever heard of the BOSS 302 Rev Limiter? The legendary, and almost impossible to find, Boss 302 rev limiter prevented the engine from spinning past 6,150 rpm.

http://www.boss302.com/rev.htm
https://www.hotrod.com/articles/rare-1970-mercury-cougar-boss-eliminator-may-finest-unrestored-example-existence/006-wyrwas-1970-mercury-cougar-boss-eliminator-rev-limiter-jpg/
https://www.hotrod.com/articles/mostly-original-1970-ford-mustang-boss-302-deserved-concours-restoration/