I agree and I’m with Dan on this. I’d also say no matter what test is out there saying how great they are, I’d only use 340 exhaust manifolds is if I had a set collecting dust on the floor.
The MP book suggests using one 340 manifold on one side and a Magnum manifold on the other side. At least the drivers 340 manifold will fit. The passenger side has plenty of room, IIRC correctly.
If manifolds are a must, the above is what I’d do but realistically I’d do headers. There just better all around.