Roger that on the 318 motor, wife had a ‘71 Duster no less. Hated to see that car go, damn winter salty roads here. And headers...... had a set and dual exhaust on our ‘67 Mustang Fastback. Loved that tinny exhaust sound going through pipes. And problems...... anything you can imagine, nothing like ball and socket and stainless tubing these days.
First to admit my road runner is long gone but not dead. Current car is ‘13 Boss Mustang but it has as named the road runner engine. Low horsepower for these days but can tach at 7K rpm. Road runner was about 5.4K rpm redline if I remember correctly. Engine supposedly develops 444 net HP. Love these mufflers, straight throughs of coarse- big difference from 50 years back. Only exhaust part I changed at all.
But wait, I’m sorry on much ado about nothing here. Supposed to be manifolds for sale and I’m sidestepped as I do way more than I should. One thing leads to another I suppose. Best wishes with sale.