383 power upgrade help

Regarding Trick Flow not recommending their heads for anything under 4.320 bore. The 383 bore is only .070" smaller. You're tellin me that .035" per side somehow keeps the Trick Flows from working on a 383? I'm callin horse crap. If the gurus wanna start talkin about valve shrouding and all that other crap to make themselves sound smart, I'm callin horse crap on them too.