I've been looking for an exhaust upgrade for a while for my 64 cuda, and finally settled on the durango manifold swap. I had a problem with the driver's side manifold dumping directly on to the starter, so I ended up using two passenger side manifolds and mounting one backwards on the driver's side. Ghetto? Mabe, but it worked. My exhaust guy ended up putting dual exhausts with flow master 50 type mufflers, can't remember the name. The car sounds waaaaay better and has a lot more oomph to boot. Just wanted to let you guys that's a pretty easy, cheap way to do it. The only thing I did have to modify was lifting the motor about 1/4" with a spacer. I'll try to get pics if anyone is interested.