Punk + 70s = ENGLAND, starting with Sex Pistols. Any so-called "punk" movement in the US was well after it happened across the pond
Sex Pistols or "Anarchy" t shirt (sleeves ripped off, of course), skinny leg jeans (like Levi's 501s) with slashes held together with tons o' safety pins. Spike the hair or do a fauxhawk, use a spray-on temporary color. Leather wristbands/neckband with studs (available @ Hot Topic), safety pins for earrings or skull earrings. Doc Martens if you have 'em or can borrow 'em; otherwise go to a thrift store for any big black clompy boots that'll fit ya.
My BFF & I were trying to throw down this look in the early 80s, with limited success and MUCH criticism in our small hometown in rural Texas
*rummages for old photos to see just how funny it was*