C-3 intake manifold bolts

[Terry M.]

Re: C-3 intake manifold bolts

Scott-----
On small blocks, GM generally used black phosphate-finished manifold bolts for engines with cast iron manifolds (i.e. to be painted) and zinc plated for those with aluminum manifolds. For big blocks, I'm not sure if the same practice was used. However, as you mention, it's really a moot point. Engines with cast iron manifolds will have the bolts painted.

Joe,
I can't say for midyear aluminum SB intakes, but my 1970 LT1 has mostly black plated (let's not get into what it actually is) or natural fasteners. I say mostly because some are still covered with enough aluminum paint that I can not tell the finish underneath, and I can only address those that have lost some of the paint, and have not corroded.