Trying to figure out where 2 bolts go on my C2. Bolts are 3 3/4 inch long with threads covering only 1 inch of the shaft. Head is 1/2 inch with the HHW headmark. Any assistance would be greatly appreciated. Thanks.
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Re: C2 bolt identification
What is the bolt size?
I assume it is a 5/16"-18 X 3 3/4" or 5/24"-24 X 3 3/4" bolt since the hex head size is 1/2". I also assume that the 3 3/4" length is the effective length with a thread length of 1". Does the hex head have a "ridge" or is it just plain? A photo might help.
What is the actual year of the car? This "C2" description is too vague. Not all 1963-1967 Corvettes use the same bolts.Last edited by David L.; July 27, 2013, 10:50 AM. -
Re: C2 bolt identification
David, just uploaded photos. Working on a 66 and 67. Thanks.Comment
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Re: C2 bolt identification
John,
If the length measures 3-3/4" from the underside of the head to the tip, then it looks like a 3/8-16 x 3-3/4" regular hex. I don't recall seeing any HHW headmark bolts on midyear Corvettes, but someone else might have.
If I have figured the bolt size correctly, it couldn't be used in too many places. That is the size for the steering box top cover bolts, but those should be Grade 5, not the Grade 2 shown in your photo. I think the steering box cover bolts are black phosphate.
It's also near the right size (depending on how you measured the length) for the following:
327, Upper and Lower inboard holes of the front A/C compressor bracket (C60-C1, item 8), or water pump to engine block bolt, but again I think those should be Grade 5 bolts (not Gr2), and closer to 3-3/8" long
427, lower alternator bolt (L36-A3, item 9), but I think that should be a Grade 5 bolt.
It could be a power steering pump bolt (N40-A2, item 10), which I think should also be a Gr5 bolt.
I don't see any bolts that size that are supposed to be Grade 2 like the one in your photo, at least not for a '67, and since I don't remember any "HHW" headmark, I'm thinking that is an aftermarket replacement bolt.Comment
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Re: C2 bolt identification
Scott, it is 3 1/2" from tip to under head, not 3 3/4". Does that help narrow it down?Comment
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Re: C2 bolt identification
John,
No, I checked everything that was 3/8-16 x 3"+ and all I came up with were the bolts listed in post #4, not including some of the black phosphate Gr8 bolts with the circle headmark used on exhaust manifolds and a few other places.
I agree with Michael that it's an aftermarket bolt shown in your picture, but that doesn't really answer your question about where it goes (or maybe more accurately, where did it come from?). If it wasn't used in one of the three locations I mentioned in post #4, then I would guess it's just an aftermarket bolt that someone used because they could make it fit anywhere a 3/8-16 bolt could go, regardless of length (within reason).
If it wasn't used to replace an exhaust manifold bolt, or to replace one of the bolts that secures the alternator, water pump, A/C compressor bracket or power steering pump to the engine, I don't know where else a 3/8-16 bolt in that length range could go.Comment
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Re: C2 bolt identification
With the thread length 1" long I count 16 threads in your photo. The bolt would then be 3/8"-16 X 3 1/2" and with the "HHW" marking I would say it probably came from a hardware store. The bolt length is measured from the tip to under the head.Comment
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Re: C2 bolt identification
Originally the bolt was 3 3/4" long with a 1/2" hex head which in most all cases would be a 5/16" bolt. However, since the bolt is actually 3 1/2" long is the hex head 1/2" or is it really 9/16". Since it is probably is a hardware bolt it really does not matter. I clearly count 16 threads in what is described as a thread length of 1 inch (see photo) or is the thread length actually about 7/8" long.
Why am I wasting my time on this?Comment
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