Radio-TV personality Jean Shepherd -- who when on mike lays it out with hoarse, fraught whispers of excitement -- has been in the nostalgia biz long before the current infatuation with the '30's and '40's; and his sorties into an Indiana boyhood, with essentially the same persona as in In God We Trust All Others Pay Cash (1966), are still hilarious, tender and rooted in copacetic recognitions. Newcomers would be advised that Hohman, Indiana, was Heartland, ""nestled. . . between the looming steel mills and the verminously aromatic oil refineries encircled by. . . city dumps and fetid rivers."" And the Shepherd cult will be happy to know that the Old Man still wears a pongee shirt on vacations and that Mother still turns out meat loaf and Jell-O. The title story, which tells of the Junior Prom with constricting rented garments, gleaming girls and the high point of a bourbon-induced vomitin, is pretty funny. Shepherd also matches its frenzied hyperbole in others about a day at the State Fair, a Jukes horde next door, a sudden death top contest, two unnerving dates and an annual vacation trip. These stories appeared in Playboy and with Shepherd's continuing and new audience (via a NET series) there will be a substantial readership, once more raising the flag at Hudson High.