The commingling of musical theatre with sci-fi and horror B-movies always seems unlikely no matter how often it happens, but it has yielded some much loved additions to the musical theatre canon.

It’s been more than 25 years since LITTLE SHOP OF HORRORS first came to the stage, based on a 1961 cheapie flick, and longer still since the original ROCKY HORROR SHOW. Strange too, given the latter’s lasting youth appeal, that even the youngest members of the first ROCKY HORROR cast are now pushing 60.

Recent years have offered new “sci-fisicals” and “musical zombedies,”: titles such as ZOMBIE PROM and THE EVIL DEAD: THE MUSICAL have captured the fancy of audiences seeking some tunes with their terror, and Bruce Kimmel’s excellent THE BRAIN FROM PLANET X played Los Angeles several years ago prior to its Off-Broadway run.

Like LITTLE SHOP before it, The Met Theatre’s new show HEAD: THE MUSICAL is based on a low-budget ‘60s public domain horror movie. This time it’s THE BRAIN THAT WOULDN’T DIE, an awful but thoroughly enjoyable bargain-basement twist on the Frankenstein story, wherein a doctor seeks a body for the severed head of his fiancé.

It doesn’t take Einstein, Dr. Ruth or Christine O’Donnell to hypothesize that a show named after and starring a disembodied head is going to contain at least a hatful of blowjob jokes. In fact the show would be a handy resource if someone were to compile THE BLOWJOB JOKE ENCYCLOPEDIA. Which could then be turned into a musical. Or not.

It’s hard to completely dislike a B-movie spoof that references both THE 400 BLOWS and LA DOLCE VITA within its first minute, but writer/composer/lyricist Kevin Fry goes too often for the cheap laugh and the easy shock. The show’s best dialogue is lifted directly out of THE BRAIN THAT WOULDN’T DIE, which is a claim no script should ever have to make.

Fry’s music is a mixed bag. At best, it effectively evokes just-for-fun ‘50s and early ’60 rock (think HAIRSPRAY), but most of the songs are generic and unmemorable. “Body Beautiful,” a sexy ditty sung by a stripper called Suductra (Amber Faith), sounds like something made up on the spot by a beginning improv performer. “Jeannie,” a naughty tune sung by an amorous swimsuit contestant (sensing a theme here?) uses the F-word as its punch line so many times, even Beavis and Butthead would be nonplused.

HEAD’s 11-member cast works hard to overcome the uninspired material. Fiona Bates gives the evening’s best performance, playing a long-ago scorned flame of the doctor. Bates plays her character with sincerity, and as a somewhat tragic figure, and lets the laughs come out of her situations and characterization. Bates also delivers her one song, “Damaged Goods” beautifully, maintaining her character while belting up a storm. Also excellent is Mark Pinckney, playing Kurt, an Igor-ish lab assistant. Pinckney is also very funny in a cameo as a dirty old man auditing an art class.

As Jan, the pretty young thing who loses her head, Stephanie Ann Saunders gives a likeable and strong performance. She doesn’t go for the shrewish approach of the movie’s main character, a wise choice, and one that better furthers the story. Becca Battoe plays Jeannie, a nymphomaniac who tries to seduce the doctor. She delivers the aforementioned unfortunate song with complete commitment, and a terrific singing voice. Battoe’s star quality, energy, and beautiful legs make her a scene stealer whenever she appears. David Bickford and J. Scott also do well in multiple ensemble roles. Charles St. Michael, playing the in-over-his-head doctor, sings well, but gives a mostly smug performance that doesn’t serve the story particularly well.

Director Flint Esquerra uses every inch of the small stage to tell a story with multiple locations. A drive-in movie effect is used for some scenes, and is effectively cheesy. Esquerra keeps things moving fast, but allows his fine cast their moments. The director can’t be blamed for poor material, but does shoulder some responsibility for content that, if not improved, should have been cut. Paul Koslo’s set solves staging dilemmas (a car, a disembodied head, an operating room…a disembodied head) with effective simplicity.

Perhaps the best thing about HEAD: THE MUSICAL is that the director and performers don’t play everything for camp value. Oh, the show is plenty campy, but that quality comes out of the sincerity with which the story is told, and the material delivered. The movie on which this show is based is a camp goldmine, but only because it’s played so straight. This stage adaptation succeeds in a similar way.

HEAD: THE MUSICAL plays Fridays at 9 p.m., Saturdays at 8 and 10:30 p.m., through Nov. 6.

Book, music and lyrics by Kevin Fry. Directed by L. Flint Esquerra. Musical director: Robert Shaw. Produced by Gabrieal Griego and Paul Koslo. Presented by The MET Theatre. Based on the motion picture “The Brain That Wouldn’t Die.”

WHERE: The MET Theatre, downstairs in the Great Scott Theatre, 1089 N. Oxford Ave., Los Angeles, CA 90029. This is one block east of Western Ave. and a few steps south of Santa Monica Blvd. There is parking available ½ block east of the venue on Santa Monica Blvd. in the Earl Scheib lot.

ADMISSION: $20. Students and seniors $15.

RESERVATIONS: (323) 960-5770 (323) 960-5770

ONLINE TICKETING: http://www.Plays411.com/headthebrain