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Old 04-04-2023, 01:51 PM   #1
72SB
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72, 6 cyl. engine/chassis ground strap?

Did these trucks have braided ground straps from valve cover to firewall and frame to body and or other positions?

without flipping through every non numbered non indexed pages of assembly manual...I am not seeing them
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Old 04-04-2023, 01:58 PM   #2
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Re: 72, 6 cyl. engine/chassis ground strap?

my 68 does:

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Old 04-04-2023, 02:24 PM   #3
72SB
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Re: 72, 6 cyl. engine/chassis ground strap?

Thanks, saw this pic in your post

I don't currently have any problems re: electrical but notices I have no ground straps other than battery to block and PS fender. My 67 Camaro has them both valve cover to firewall and frame to lower firewall. Just assumed the C10 would have similar.

engine firewall have been painted by PO...perhaps they were removed then...
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Old 04-04-2023, 08:00 PM   #4
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Re: 72, 6 cyl. engine/chassis ground strap?

Absent actual ground connections with wire/cable/straps, connecting engine-frame-body together, current will find other paths.
Brake lines, e-brake cable and throttle linkage can provide paths. This is not a good thing.
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Old 04-04-2023, 08:12 PM   #5
72SB
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Re: 72, 6 cyl. engine/chassis ground strap?

Understand the need for ground straps and assume factory put them on.

The ? was "where" were they installed. I certainly can add, and will, ground strap from VC to firewall and frame to firewall. On a close look, not seeing holes or studs where VC to firewall would go but can take a cue from the panoramic view in post 2. Was going to go from frame up to firewall with another.

Have never had any electrical issues in the year plus since I have had the truck. Cleaned up wire harness with new tape and installed headlight relay harness (grounded to core support) and replaced a fatigued battery cable are the only "electrical" items I have touched on the truck. Was just noticing the other day...wtf are the ground straps, so thought I would ask. Ordered some and will install in a few days.

If anyone has diagram from assembly manual to share that note's locations, please post.
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Old 04-04-2023, 08:47 PM   #6
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Re: 72, 6 cyl. engine/chassis ground strap?

Look around for pics, if people don't post more. There should also be ground straps from the engine to the frame. Sometimes people paint over the holes in the firewall where a ground strap would have connected. I added three just for grins before I got into the problem mentioned below. I'm not over-excited about originality on my truck, given the amount of changes made by both the PO and my F-i-L. I was chasing hard starting gremlins (and some seriously hot engine temps) that had plagued my F-i-L from date of purchase. Turns out that there was a "cascade" of things that were incorrect that caused that. I finally ironed it out, but it took me several months, once I got tired of the issue.
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Old 04-05-2023, 12:16 AM   #7
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Re: 72, 6 cyl. engine/chassis ground strap?

My 69 6 cyl has one on the firewall and one on the bottom of the P/S frame rail screwed to the cab mount (front) support .
Hope that helps. I am sure someone else will post a picture of a 72 for you.
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Old 04-05-2023, 12:40 AM   #8
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Re: 72, 6 cyl. engine/chassis ground strap?

-
Here is a pretty good thread on ground straps....

http://67-72chevytrucks.com/vboard/s...d.php?t=422234

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Old 04-05-2023, 01:23 AM   #9
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Re: 72, 6 cyl. engine/chassis ground strap?

For a BBC. I imagine a SBC is the same, not sure about a 6 cyl.

Five ground straps connect the body to the chassis. The OEM strap lengths installed into this truck measured end to end are:
• LH valve cover strap: 13.1/8”
• RH valve cover strap: 10.1/2”
• RH inner fender, cab and bed straps: 6”

Each valve cover ground strap connects from the cover’s outer rear screw to the firewall’s lower pocket nearly parallel of the screws. The strap’s open terminal slides onto the valve cover screw. The closed terminal mounts to the firewall with a 3/8” hex flange tap screw. The screw threads are 1/4” x 5/8”.

The cab, RH inner fender and bed ground strap terminals assemble as:

• The strap’s small terminal with teeth connects to the frame rail and cab mount walls using a (GR 5) 7/16” hex bolt, hex nut, and two ground washers each. The bolt threads are 1/4-20 x 3/4”. A ground washer is placed against both sides of the wall.

• The straps other terminal connects to the inner fender, cab rail and bed cross support using a 3/8” hex flange tap screw each, with the screws inserted from below. The screw threads are 1/4” x 5/8”, and the heads are stamped “RBM”.

The cab strap connects to the RH front cab mount’s rear outer wall, and to the cab rail’s bottom located approx. 2” behind the cab mount.

The RH inner fender strap connects to its bottom using the smaller of two holes located in its front LH corner. The larger hole is for a radiator overflow drain hose. The strap connects to the RH frame rail’s outer wall by the first hole located below its upper lip, found nearly parallel of the water pump inlet.

The bed strap connects to the rear bed cross support’s bottom, and to the RH frame rail’s inside wall using the hole located nearest the support.
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Last edited by 71CHEVYSHORTBED402; 04-05-2023 at 06:39 PM.
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Old 04-05-2023, 07:00 AM   #10
Palf70Step
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Re: 72, 6 cyl. engine/chassis ground strap?

The way I have done all of mine are

Battery sad ( - ) cable to block,
battery cable from block to frame
Battery cable from frame to front core support
Instead of the valve covers I have a strap from each head to the firewall. ( on my last 250-6 I went from where the z bar bolts in to the firewall with a very beefy strap).

Strap from the cab to frame (most time I use 2, one of each side.
Bed to frame
I also take each taillight socket and run a ground to the frame.

I also set up a bus bar inside the cab to run my grounds too, then had a wire from there thru firewall to the location I have the ground from the block and frame.


May be an overkill, but grounding issues on old stuff can drive you really crazy. This has always seemed to solve any electrical gremlins on my trucks.
t
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Old 04-05-2023, 10:56 AM   #11
72SB
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Re: 72, 6 cyl. engine/chassis ground strap?

Thanks LocDoc. The first post in the thread link you posted is what I was looking for and matches what I "thought" the factory locations are.

I ordered some copper straps from Amazon. There are pages of them available in various sizes to choose from.. Got 3 for $9

I have sheet metal bolts and star washers to secure them.
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Old 04-06-2023, 04:46 PM   #12
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Re: 72, 6 cyl. engine/chassis ground strap?

Put these 2 ground straps on. VC/firewall & firewall/frame.
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