Very interesting thread guys. Good info here. I just had to go check mine, which I have little or no doubt is the original 1971 351C non-A/C Part number is D0OE-8146-C, made by Barnum Bros and is fiberglass. To be honest, I've not seen an original plastic shroud for any year, but what do I know!! Been proven wrong before.
Ken is yours for a 9 car? That would make sense that yours is narrower I guess.
Yes, yours is the correct standard fair for the 351C line. I don't believe there is a plastic one either, I did have an aftermarket plastic one years ago for my '71 429cj Mach, did the job until I found the original fiberglass unit similar to the one we are discussing in this thread. Yes, this is all about the correct shroud for the 429cj vert restoration I am doing. These are much thinner then the 302 and 351C shrouds, easy to spot in cars, hence why I questioned when I saw the picture above. we all learned a little today... Cheers