Is there a website which shows pictures of the proper assembly of the bi-metallic spring on the exh manifold heat riser valve?
The picture in my 64 Chevelle shop manual seems to be wrong.
They show spring backwards from what works.
(as verified with torch heating manifold and spring to see what the spring does to heat riser valve)
I wonder if the exhaust manifold is shown in the Nova, full size car, or truck manuals.
Anyone run into this?
btw: is there a source for new springs?

i have some good used ones .you pay shipping.

As the spring heats up it relaxes and the weight on the heat riser opens it. Is that hows yours works? The shop manual could have the negative reversed when they printed it.

I think it actually winds up, but yeah that's the idea.
The weight and exhaust flow open butterfly inside manifold.
There was also another spring, a counter-acting spring. I don't think that one is bi-metallic.
I had an engine sitting that I trusted to be right and assembled new one that way and it works.
BTW: If not obvious the shaft needs to be clean so it can move freely. Penetrating oil and light tapping side to side usually free them up.

Pete