the standard rear ratio is 3.90, should gitty up fine, but the original ratio with an OD trans was 4.11 .... maybe by "Corvette headers" you mean the original rams horn manifolds? the Vettes had slightly larger diameter, but any rams horn would be fine for a normal 283 .... the setup you bought would be for general driving, especially highway speeds with the OD, if you're into spinning the tires a manual trans would do it easily, mine does
Bill
