Chevy II long tube headers.
63 Chevy II, Chassisworks clip, LS1, T56 tranny. I did not use the supplied motor mount adapter plates. The quality seemed good. I did spend a little time to deburr the holes and used a file to break the sharp edges. On my car the fit was good with the exception of the driver side O2 sensor. It would not work in the spot designated for it as it interfered with my stock floor pan. I ended up putting a plug in the bung and welding a new bung just downstream of the header. Satisfied overall.
Best stainless manifold for the price
I'm not a big AFE fan, and looked hard to find a solid stainless manifold elsewhere. But all my research kept leading me back to AFE. They have a quality design that will last for the life of the truck. So if you are looking to improve your exhaust flow, lower EGTs, have a place to put your EGT temp sensor, then this is probably the best manifold for the 5.9L.