Editing Pontiac head problems 64 326 heads or 78 6x heads for a 1965 689

i have a 1965 pontiac 389 bored 30over.dont know if i should use 1964 326 2 bbl heads,8.6cr or 1978 6x 4 heads only 220 hp on a 400.this motor will be topped off with a tripower to run on todays gas.i would like to see 300 plus horse for the street.please advise

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−	~~#REDIRECT [[Choosing cylinder~~ heads]]	+	i have a 1965 pontiac 389 bored 30over.dont know if i should use 1964 326 2 bbl heads,8.6cr or 1978 6x 4 heads only 220 hp on a 400.this motor will be topped off with a tripower to run on todays gas.i would like to see 300 plus horse for the street.please advise