Mystery bolts (help please)

[Mrbill426]

I have these three bolts I have not been able to figure what they are for.     I suspect either front cover or maybe intake manifold somewhere.  On the front cover all the bolts to attach it and the water pump to the block are accounted for.  I am about to button up the oil pan so I hope they don't belong in the bottom end somewhere.
For the  two 3/8" bolts I thought maybe the fuel pump, but then why different lengths?

Any ideas folks??

Thanks

[anlauto]

The blue one with the "H" is for the thermostat housing in my opinion...

[Mrbill426]

@anlauto thanks, that is a start 

The blue one with the "H" is for the thermostat housing in my opinion...

[anlauto]

Sorry, my phone was ringing off the hook when I typed my last response, I didn't get a chance to finish my thoughts...

Is it a small block automatic ? I'm thinking the other two could be for the reinforcement bars that go from the bell housing to the side of the block on automatic cars, OR if and AC car they could be for the compressor support brackets.

[Mrbill426]

@anlauto yes 340 AT so you might be right on reinforcement bars; I have to figure how they mount when I get the transmission back from the re-builder.  The "H" bolt is too small for the thermostat housing, it is 5/16" and they appear to be 3/8".

Sorry, my phone was ringing off the hook when I typed my last response, I didn't get a chance to finish my thoughts...

Is it a small block automatic ? I'm thinking the other two could be for the reinforcement bars that go from the bell housing to the side of the block on automatic cars, OR if and AC car they could be for the compressor support brackets.

[anlauto]

Oh...now that I turn my head sideways I see it's smaller...quick glance thought it was 3/8''. 

Those markings are found on carb mounting bolts and front sway bars hoops, but it looks too short to be either of them...unless it's about 1" long

[anlauto]

Blue one could be a negative battery cable-block 

[Burdar]

I had "H" bolts holding my fixed fan/spacer onto the water pump.  They were really long since there was no fan clutch.  Would that bolt be used to attach the fan clutch to the water pump on a 340?  That doesn't explain why it's blue though...never mind.

[benguin]

Is that the right size for the inspection cover plate on the transmission?  I don't recall mine being "H" bolts though, but they don't have a washer.

[Mrbill426]

@anlauto sorry I am drawing a blank ... what is that?

Blue one could be a negative battery cable-block 

[benguin]

@anlauto sorry I am drawing a blank ... what is that?

Blue one could be a negative battery cable-block 

If Alan means the negative battery to block ground wire, mine looks more like the shorter of the other two.  It's a 1/2" head with a very sturdy washer but a different stamp (which isn't unusual).

[anlauto]

Yea...I was just throw darts at a dart board...I don't think it is the negative battery cable bolt, although it appears to be the right size...

[tparker]

What Engine? Here are a few options I was able to pull up that seemed to match. A couple are outside of the e body years, but I through them in just for completeness

Short boat anchor bolt
a/c compressor rear support bracket mount left and right sides 3/8-16 X .875"
A/C compressor to LH cylinder head mounting bolt 3/8-16 x 1.00"
1970 small block AC support bracket right side to manifold bolt 3/8-16 x .75"
68-69 big block body ground cable to RH 3/8-16x.73

Long boat anchor bolt
68-74 6 cyl Thermostat housing bolt 3/8 - 16 x 1/15"
68-69 big block alt support strap 3/8-16x1.08" 
68-69 triangle bracket to water pump 3/8-16x.875"
6 cyl alt Support strap to cylinder 3/8-16x1.08"

H bolt
70' small block timing cover mounting bolt 3/8-16 x 1.00"

[Mrbill426]

@anlauto  The engine colored bolt is a 5/16" bolt, 3/4" long with a 1/2" hex head.   The prior owner installed a Holley using studs so carb mount is out, plus there is only one like it.  As for the larger ones the tranny supports have their bolts taped to them.

@tparker it's a 340 with A/C, and thanks for the data I will see if those two match and are missing from those assemblies.

@benguin I will check on the tranny cover idea too.

Thanks guys!

Yea...I was just throw darts at a dart board...I don't think it is the negative battery cable bolt, although it appears to be the right size...

[anlauto]

Isn't every good project supposed to have left over hardware ?