We're rolling north on I-75 toward Atlanta in a '69 Cadillac convertible, top down, a rangy country singer and his road manager smoking cigars up front and two dignified members of the press scarfing Moon Pies in the back. The sun's a hazy fireball, turning the long ribbon of asphalt, the tall Georgia pines, and the hot, heavy air itself a delirious, misty pink; the only thing missing is a soundtrack. Suddenly, though, there is one, a rockabilly howl so frisky and sly you'd think there was a baby bobcat in this car: ''I'm a ca-a-a-lm, c-o-o- o-l DADDY!/ In a lo-o-o-ng, re-e-ed CADDY!/ Cadillac Man!/ (Cadillac Man!)/ I'm a Cadillac Man!/ (Cadillac Man!)''
Marty Brown's feeling fine, and no wonder. Only a year or so ago he was cutting tobacco and working as a plumber to make the trailer payments and support a wife and two kids in his hometown of Maceo, Ky. (population 400), driving down to Nashville every chance he got with his guitar and a pillowcase full of songs and getting the doors of Music Row slammed in his face. Then, in an apotheosis so dramatic, so Nashville, that it was documented on 48 Hours last spring, he got his big break: After spending the night in a Nashville alley and not for the first time, either he came across the words ''Trust Jesus'' scrawled on a sidewalk not just any sidewalk but the one outside the BMI building. He went straight upstairs to the office of mover-and-shaker Kurt Denny (then associate director of writer-publisher relations), blew him away with his songs, and lo, the doors of Music Row did open.
Now his debut album, High and Dry, has been released on MCA, and critics are comparing his ''choke-and-moan'' vocal technique to the hallowed Hank Williams Sr. and his low-down country-blues style to the young Elvis Presley. With a musical sensibility rooted in the deeply rural traditions of '50s country music, Brown's being touted as the real deal, and boy is he ever. Until this year he'd never been more than a couple hundred miles away from blink-and-you-miss-it Maceo. Now, at age 26, he's not only played at the Grand Ole Opry, he's also seen the Atlantic Ocean for the first time (he liked it), eaten his first Chinese food (didn't like it), and taken his first plane ride (hated it).
But not everybody is rushing to hail Marty Brown as the man who's putting the country back into country music. To be sure, Brown's two singles, ''Every Now and Then'' and ''High and Dry,'' have been getting played on smaller radio stations, and TNN and CMT have been airing the videos. But the major country radio stations who are doing just fine with the traditional but incomparably slicker ''hat acts'' like Garth Brooks, Clint Black, and Alan Jackson have yet to play his music.