Use Chevy small block V8 exhaust valves, springs, retainers, and split keepers if you choose. Are they technically right?- - - - -No. Will the engine care? Also no. Way too many people bow down and worship 75 year old factory parts manual numbers like Moses brought them from Mt. Sinai, chiseled on stone tablets by the hand of the Almighty!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!