I bought some header flanges off of eBay and a kit from summit racing with a bunch of pre bent 1 3/4 pipe and collectors.
worked great and was a fun project. The poly went in a truck so plenty of room, but im sure a set for an A body could be accomplished the same way.
The poly is a neat engine but has some drawbacks. It is as wide as a 440, heavy, and aftermarket support is very thin- and if you ever need to change a rocker arm with the engine in the vehicle it is a pain in the ***
The one in my truck runs great. Lots of torque, even below idle speed. We balanced the crankshaft and it is very very smooth.
