Alternator Belt Tension Adj Bolt

[camaronut]

Is there an absolutely factory correct alt tension adjustment bolt available?  I just got the bolt kit which has the pivot and adjustment bolt and it’s all black EDP coated.  The pivot bolt yeah, but I’m pretty sure that the adj bolt was zinc plated.  The flat faced bolt I see out there doesn’t look right either.
Anything out there that’s correct???

[David K]

Hoping someone with a judging manual will chime in…

[camaronut]

Like a dumb-a$$ - I have one, and it shows an original bolt.  Only shows one of three examples - I'd like to see other REAL ones. 
They should be marked with either - "WB", "NAT" or SB headed bolts.

Can't believe CHQ makes the kits with the wrong plated adjustment bolt. -

Ehhh whatever, I should have better things to worry about!!!  LOL!

[David K]

Doh! But why wouldn’t all 3 be shown? Does the manual give you a choice of marked head?

[169INDY]

Bolt- Bright Zinc
Lock- Mag Phosphate/Black Oxide
Flat- Bright Zinc

Resources: Hot Rod 1969 Rod Test V8 302 & GM press photo of 1968 V8 302

[camaronut]

Doh! But why wouldn’t all 3 be shown? Does the manual give you a choice of marked head?

  Nope - Just the one.  Whatever.  The manual states that they should be marked with either - "WB", "NAT" or "SB" headed bolts.

And Jim - thanks for the pictures - really helps.  Never knew about the black oxide lock washer.

I have a picture of the bolt from an untouched 69 Z, and it looks like nothing that's available repro...but - I could be wrong.

I'd post the picture, but it's way too large.

[169INDY]

Wonder if  R-B-W alt bolts would be acceptable ?

I need to dig out my 68Z bolt & look at it.

There must have been a variety of qualified GM vendor-suppliers for this hardware. I will look for additional road test samples, my 67/68 - 396 Car photos from road tests are not much help since the bolt head washer combo is rear facing and not clearly visible in most engine photos

[camaronut]

I don't get my car judged by anyone but myself....I just want it right.

[Edgemontvillage]

Most of the available repro alternator bolts are incorrect as they are Grade 2 or ungraded rather than Grade 5 per the originals. Several different manufacturer's head markings are possible. Below is a photo of an original Grade 5 bolt (evidenced by the three radial lines on the head), manganese (black) phosphated lock washer and the thick, plain silver cad plated washer from Skip L's late production survivor 1969 Norwood X77 Z/28.

[Edgemontvillage]

[David K]

For Indy on post #6, I have countless stories about parts runners leaving the Final Assembly property to go get nuts/bolts/washers and assorted items from surrounding hardware stores. I’m not sure how true this is, but the logic of the discussions  makes me more of a believer than non.

[KurtS]

That is the correct stack - GM used this setup for many years. I saw one on a 75 Chevette in a junkyard the other year - exactly the same.

Yes, these bolts are commodities - the plants had multiple suppliers. Pretty common to see different head markings on different sides of the car. They filled the bins by part #, supplier didn't matter.

[KurtS]

For Indy on post #6, I have countless stories about parts runners leaving the Final Assembly property to go get nuts/bolts/washers and assorted items from surrounding hardware stores. I’m not sure how true this is, but the logic of the discussions  makes me more of a believer than non.

BS. I'm a doubter and lived it. That was the scheduler's job - to make sure the parts were on the line. Multiple suppliers and they would expedite the parts as required. All the correct sized bolts from a local hardware store would get used up in minutes.  Much more likely to use a similar bolt from somewhere else on the line.