Help, I need a little help. I've seen C3 cars and have seen some with and some without the radiator shroud extension ring. How important is this thing for cooling? I don't have my '75 running yet but should I just wait and see how hot the thing runs? The car has a brand new GM 350 crate motor and sure don't want to over heat the thing. What do you guys think? thanks for the input.

I added the ring on the 70 and it made a bit of a difference temp wise on hot days.
Just makes sense that directing the air better would work better.
Doubt you would blow up your car without one, just a bit better with one.

That could be hard to find if you cannot find a local source check vettsteve@aol.com.  I use him a lot he is a life member and local to me.  Showed me a trick to get t-tops to line up after I had given up on it.   He restores and sales C3 the ones that are beyond restoration he parts out.  There is also a place in LA if you need me to find out about let me know.  I know a shop that does business with them.