I like the idea of the Doug's with 1-5/8" tubes the whole way. This 273 will not be pushing a lot of flow (small CI) so scavenging exhaust makes sense. But I'm told you need manual steering only.
I used Doug's on my 66 Barracuda with my 5.9 swap.
Power steering car. I just had to dent the tube next to the coupler. Might clear completely if you used a Borgeson coupler. I also had to dent the oil pan slightly. Torsion bar and steering column run through the headers on the drivers side.
Yes, they are 3 pieces on each side. No issue with leaks on the flanges or slip joints.