Engine ground question

Fireguyfire

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I’m just finishing up the engine bay on my 1970 300 convertible after going through the engine, and pulling the generic aftermarket wiring harness the previous owner had installed in the car.
My question is regarding an engine ground strap. Of course the negative battery cable comes off of the top front of the engine, and also has a body to ground wire off of the negative terminal.
I’ve restored a bunch of B and E bodies over the years, and they usually have a ground wire running from the firewall to one of the engine to transmission top bolts.
My engine doesn’t have that, but it could have been easily removed. I’ve been through the FSM and see no reference to a rear engine ground, but I thought I would double check here before I start live testing the wiring.
Should there be a firewall to engine ground strap on my 440?
 

Davea Lux

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I’m just finishing up the engine bay on my 1970 300 convertible after going through the engine, and pulling the generic aftermarket wiring harness the previous owner had installed in the car.
My question is regarding an engine ground strap. Of course the negative battery cable comes off of the top front of the engine, and also has a body to ground wire off of the negative terminal.
I’ve restored a bunch of B and E bodies over the years, and they usually have a ground wire running from the firewall to one of the engine to transmission top bolts.
My engine doesn’t have that, but it could have been easily removed. I’ve been through the FSM and see no reference to a rear engine ground, but I thought I would double check here before I start live testing the wiring.
Should there be a firewall to engine ground strap on my 440?
It should have one. The ground strap was usually attached with a self tapping bolt, see if you can locate the hole for it.

Dave
 

Fireguyfire

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Thanks Dave; can you enlighten me on what gauge of wire to use, and which bolt on the tranny/engine connection to use?
I do see the hole in the firewall where it should go on that end.
 

Davea Lux

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Thanks Dave; can you enlighten me on what gauge of wire to use, and which bolt on the tranny/engine connection to use?
I do see the hole in the firewall where it should go on that end.

I do not know of anyone doing an exact replacement of the woven strap, probably best found on a donor car. www.summitracing.com has some that are close to the original.

Dave
 

MrMoparCHP

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In 1970 there should be a 10ga wire on the rear of the passenger side head that connects to the firewall near the ballast.
Later years it was moved to the negative battery cable and connected to the core support.


Alan
 

MrMoparCHP

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You can see it to the right of the ballast.
2021-12-04_004.jpg



FYI, I have never seen a braded ground strap from the factory on any Mopars of this era.

Alan
 

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The ground never came off the engine to trans bolt. It came from the cylinder head.

agree the flat woven ground is not factory.
 

MrMoparCHP

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On the big block there is an exposed (unused) bolt hole to the rear of the head (topside), rear of the intake.


Alan
 

Fireguyfire

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That makes sense as all of the b and e body cars I’ve restored have had a regular “wire” ground.

Anyone help me out with a gauge size for it?
 

Wonderwagon

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You'll see the ground strap on the left above the heater box curled up and out-of the way

20220311_162507.jpg
 

JimmyG

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The wire is usually an 8, although a 10 will work just fine.
The placement of the ground wire on the rear hidden back of the head bolt as described by a prior submission, and the self tapping bolt on the fire wall, requires two different sizes of terminal. It is easy to forget this and then have to make an adjustment to your efforts. Don't forget to leave enough length for minor engine movement, unless you are doing power shifts and need a whole lot more! Hopefully not.
 
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