Been a set on my '70 Duster since it was new; it's always been a drag car. Slip-fit primaries, one on each side goes through the apron, collectors bolt on using tabs. Clears a huge oil pan & the trans, tight at idler arm. Tight at brake lines. Requires adapters at the cylinder head if your heads have the OEM bolt pattern. Flanges are real tight if you use 13/16" spark plugs, but 5/8" are a breeze. No interference with my 7.10x15 Moroso ft tires. No ground clearance issues unless your trailer lacks a beaver-tail.
Here's a left-side photo, with Batten W2 heads. Being an old SS/IA car, the engine location's been juggled a bit.