The C body driver side manifold has no chance of working without major modification because the pipe flange points out to the side of the block. If we cut off the flange and welded on a short section of pipe it would work great.
I would try to find a 68-69 big block HP manifold.
The C body manifold has been made to work by many people by milling the manifold so that the outlet sits closer to the engine. A lot of people have made it work.
