ABC-TV's teenage musical show, "Shindig," has moved up from 30 to 60 minutes, and has at least doubled its entertainment impact. The hourlong version bowed last Wednesday night (20) with a neat lineup of pop disk names and combos working within a topflight production that kept the stanza rocking and rolling, musically and visually for the full running time.
     Producer Jack Good, a Briton, is obviously hip to the teenage sound. There was no adulteration of the show's style and flavor by the introduction of "adult" ballads or instrumentals. It was strictly go, go, go with British U.S. combos and soloists with some ace backing by a young dance troupe who turned the swim, monkey, watusi et al. into a colorful kaleidescope of contemporary hoofology.
     The long roster of young singers were excellently paced. Standout were Petula Clark's "Downtown," Donna Loren's 10 Good Reasons," Glen Campbell's "Mean Woman Blues" and varous other numbers by Bobby Sherman, the Walker Bros., Jackie & Gayle and Bobby Vee. Roosevelt Grier, Los Angeles Ram linesman, also carried the ball with a couple of remarkably good vocals, accompanied by three of his teammates in a combo tagged The Fearsom Forsome.
     Echoing the pop charts, the show also heavily accented the British rocking combos, spotlighting the Dave Clark Five, The Kinks, Gerry & the Pacemakers and the Rolling Stones. From the U.S. crewcuts to the British mophairs, the show really swung.