I'm running the Clifford street rod headers on my 250 in a 37 Chevy. As you might already know these are sort of a block hugger design in that the collector flanges end about at the oil pan flange on the block. The rear header exhaust pipe runs sort of straight back on the left side and the front one I have the exhaust pipe running under the front of the pan and then a gradual curve to down along the right side of the frame. Since there is no crossmember under the oil pan this works. On a late model car with a beefy factory front crossmember I don't think you'll get away with that. Its mated to an Offy 4 bbl manifold and the only ache is the not too precise flange sides on the Offy. It required some file and die grinder work before everything fit the way it had to against the head.
Depending on how you can run the second exhaust pipe will be the final decision I would guess. The Langdon cast 2 piece exh manifold is a nice looking unit and appears compact enough for a good exhaust fabricator to work with.
