That is definitely a different car...dad’s car had stock original interior and never had the inner fenders cut for headers....sloth I believe he thought about doing that at one time!
i think he should still do it! They don't have to be fender exit, they can be standard longtube mandrel bent headers. longtube headers make such a huge improvement in flow IMO, you'll get a distinct gain, probbaly 10-15 HP, 15 lb/ft torque
