Manifold Heat Control Valve

At Bates Corp., they're $52.65 ...mighty pricey, in my opinion.

http://www.batescorp.com/cart/index.php?subcats=Y&status=A&pshort=Y&pfull=Y&pname=Y&pkeywords=Y&search_performed=Y&q=82958R2&dispatch=products.search

Did a search of the IH pn plus found the one 'ol beast mentioned (much cheaper than $52).

https://www.google.com/#q=82958R2+spring

http://www.oldchevytrucks.com/cart/prod ... spring||||

Did a search with the pn from above...
https://www.google.com/#q=ME188+Heat+Ri ... g&tbs=li:1

And one of just "Heat Riser Spring"
https://www.google.com/#q=Heat+Riser+Spring&tbs=li:1

To avoid the shaft seizing use some hi-temp anti-seize,the temp range should be on the label. I've used it on the pipe flange bolts and even exhaust clamps works great.

Jimmy Carter truck parts number for this spring is ME#188, and it lists for $17.75, and they would nail you for shipping too.