you forgot the magic checklist for great fitting headers P! small block, tube K, coil over shocks! I can remove my headers with the engine in the car, on the ground :P all kidding aside, the combo of big block, stock chassis, big power steering box, + working around those torsion bars is a tough chore. I'm thinking even custom headers would be a tight deal on that car. People from farther than you have hauled cars to REF in Kingman AZ to get headers made.

....and 500 cubes and 915 heads? why bother with the additional cost of a stroker.