66 dart with 360 ...what manifolds or headers?
Repeat, you had 71 logs? I had 68 logs. They are different.
I had the original '71 manifolds (not the header-looking passenger-side manifold,) and it scraped the side of the inner-fender panel HARD (simultaneously with the driver's side,) as it was being lowered into the engine compartment. It was a tight fit, hitting on both sides.
I was going to live with that tight fit, hoping I could "relieve" some of the interference, so I drove it to a custom exhaust shop to try and get some head-pipes connected to mufflers.
After looking at it for 30 minutes, the exhaust guy came to me and said, "The passenger side can be made to work, but the driver's side will never be connected... too many things in the way" (it was a floor-shifted A-833 4-speed with a Hayes, 3,000-pound pressure plate.)
I drove it home and put a cheap set of Hedman headers on it.
True story...
Guess those '68 manifolds must be a bit narrower, but they sure don't LOOK narrower....