Finish for 9418821?

[Patrick N.]

Can anyone clarify the correct finish (and head markings if known) for part # 9418821, pg H211 of 68 AIM, used to hold the gas tank support to the frame? It is also the same bolt used to hold the shifter support assembly near the tail of the manual transmission pg H200.

I ask because I see different places sell them finished as both zinc or black oxide, I also see the zinc with "A" head marking and double circle as Black Oxide-are either known / accurate? I highly doubt GM would have finished the same part differently.

Thanks for any feedback.

Pat
68 427 / 400
88

[John D.]

Re: Finish for 9418821?

patrick,

The part drawing shows phosphate per GM-4435-M, no mention at all of zinc. Hope this helps


john

[Michael G.]

Re: Finish for 9418821?

GM did not put zinc and black oxide as options on the same part.

GM 4435-M is zinc phosphate, which sometimes looks a lot like black oxide, sometimes varying shades of dark gray, it is definitely not silver . Normally there will be a code after the GM4435-M on the drawing, specifying the surface treatment to be applied after zinc phosphating, such as "Code A" which is "oil" dipped or "Code B" which is paint dipped. There are a few more.

[Patrick N.]

Re: Finish for 9418821?

Thanks guys for the clarification. Zinc seemed out of place for these parts.

Thanks again,
Pat

68 427 / 400
88