I don't see why long tube headers would be any better than Fenton cast iron manifolds on a 235. You can't have true tuned length headers on a siamesed port 235 because the exhaust pulses on the siamesed port are asymmetrical. If they are advertised as tuned length, it could only be tuned to the length appropriate to one of the shared cylinders, but not both, on each siamesed port. Do it only if you just like the look, not with the expectation of improved performance.
