This cult favorite began as Francis Ford Coppola's UCLA thesis, ending up with a professional cast and nationwide release. Teen Peter Kastner undergoes his coming-of-age rites when, urged on by dad Rip Torn, he strikes out on own and moves to NYC. Every person Kastner meets is an eccentric's eccentric, from landlady Julie Harris to cop Dolph Sweet. Kastner's new friend Tony Bill, who works at the New York Public Library and accumulates pornography on side, introduces the boy to sex and drugs. Our hero truly matriculates to manhood after his heart is broken by disco dancer Elizabeth Hartman; he settles instead for Karen Black, still enough of an unknown quantity in 1966 to play against type as "the right girl". Adapted from a novel by David Benedictus, Big Boy is afflicted with usual youthful film-class fervor, crammed full of showoffish cinematic tricks that Coppola would eventually outgrow. But one can't deny that this seminal production is both heartfelt and energetic. To improve the film's saleability, distributors Seven Arts tacked on a music score by the Lovin' Spoonful, hardly necessary but very enjoyable appendange.
~ Hal Erickson, All Movie Guide