I've used 1 3/4" Super Comps for an E body only
I relocated one tube for the drivers side
Moved the prop valve on the outside
plated the outside of the frame with a plate that wrapped the top & outside after notching the lip on the bottom
passenger side went in perfect

The collectors sit close to the floor & are tucked an inch inside the profile of the frame

That's what I did on my 73 Pro Streeter I built 15-18 years ago