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.
These headers are well worth the price. A word of advice. It is 95% certain that your check engine light will come on. This can be easily rectified with a simple flash tune. The O2 levels get out of wack which causes this. You probably should tune it anyway in order to get the full performance benefit of the headers.