1970 corvette ls5 ground straps

[Matt Callander]

Looking for some help on the proper location of 2 ground straps that were in the engine compartment on my 1970 ls5 corvette when I purchased it as a restoration project. The engine compartment was some what of a mess and 38 years of previous ownership definately resulted in some wiring and grounding changes under the hood.

I spent several hours today searching my assembly manual and I couldn't find the straps in the manual. I also tried researching the archives with no luck.
The ground straps appear to be original to the car but I could be wrong. The 2 braided ground straps are approximately 13 1/4 inches in length including the connectors. Each of he 2 straps have 1 eyelet which is closed and the other end has an eyelet which is open to allow the connector to slide over a bolt.
I suspect they may run from the valve pan covers on each side to a ground point reference.
Any help would be appreciated. Thanks in advance.

[Chuck S.]

Re: 1970 corvette ls5 ground straps

I know less about 70 big blocks, but I'm fairly sure there were no braided ground straps in the engine compartment.

Early 70s will have narrow braided ground straps on the exhaust system to the frame, but these were eliminated during the 70 MY. The lengths of the straps you describe sound too long for the exhaust system ground straps.

A heavy duty starter ground cable is shown in the 70 AIM on UPC 12, Sheet A11. Since there is no other superceding information in UPC LS5, this will be typical for the big block as well. Other grounds in the engine compartment will be the black wire harness grounds.

Earlier big block Corvettes had braided ignition shielding covering the plug wires in lieu of the sheet metal vee shields. I don't know if the shielded plug wires were used in 70, and it isn't clear from the AIM that they were.

[Chuck S.]

Revision and Addition

Further study of my AIM shows braided shielding on plug wires was used on 70 big blocks, but it is relevant only when the radio was ordered.

Detail of the shielded plug wires is shown in UPC U69, Sheet A7. What you are observing may be the remanants of the original plug wire shielding. The plug end of the shielding would have terminals that attached under the first and third bolts on the lower edge of the valve cover.

[Warren F.]

Re: 1970 corvette ls5 ground straps

Matt,

Yes, 1970 LS5 Corvettes did have those flat braided ground straps. I've had 3 '70 LS5 coupes #'s 6664, 7272 & 8373, all had them. Mine may not have been hooked up correctly, but they were attached the corner rocker arm cover bolt.

My 3 1971 big block coupes did not use these straps.

[Chuck S.]

I Knew I Knew Less About Big Blocks...

Warren, thanks for getting things straight.

I think what Matt wants to know is where do the end terminals attach. Your cars were all close to the middle of the production run...the 70 AIM doesn't show any reference to these ground straps in the UPC LS5 section, but the AIM copy used for reproduction is a VERY late edition.

[Matt Callander]

Re: I Knew I Knew Less About Big Blocks...

Warren and Chuck, Thanks for the information. Warren, do you recall where the ground straps attached? I agree that the one end would connect to the valve pan cover on each side of the engine, however, the other end I have no idea. I recall the driver side strap was connected to the wiper motor terminal but I don't know if it is correct. Any help or pictures would be appreciated.

thanks again!

[Jim T.]

Re: I Knew I Knew Less About Big Blocks...

Matt in the supplement to the 1970 Chassis Service Manual I have that is identified as Chevrolet Service News has information about the ground straps. On page 8 there is a picture showing the BB with a ground wire coming from each plug wire and two ground wires connected to two valve cover bolts. This March 1970 supplement also has information on the LS7 engine. The 454 390HP made more torque than the LS7 454 460HP, the 390 is listed at 500@3400 and the LS7 490@3600

[Matt Callander]

Re: I Knew I Knew Less About Big Blocks...

Jim,

Thanks for the info... sounds like you found the information I have been looking for. Does the picture show where the two ground straps terminate that are connect to the two valve covers? Would like to find out which bolt on each valve cover the straps are connected to and where the other end of the straps connect. thanks for your help.

[Matt Callander]

Re: I Knew I Knew Less About Big Blocks...

Jim,

I went to my service manual and found the picture of the engine showing the braided sheilding around each of the spark plug wires being grounded on the 1st and 3rd valve cover bolt from the front.

I also found a picture of the ground starps under the car that are terminated at the exhaust and cross member on the frame. I have the ground starps in place
there as well as the ground strap located by the body mount.

What I looking for is information on the 2 additional braided copper ground straps that are approximately 13 1/4 inches long that were found on my LS5. The one copper strap was found connected to a valve cover bolt and was terminated at the wiper motor bolt. I'm not sure if that is the proper placement of the ground strap since the wiper motor appears to be hung in place with rubber insulated bushings. I'm not sure the strap would serve a purpose given the wiper motor is insulated from the terminal and ground strap.

[Matt Callander]

Re: I Knew I Knew Less About Big Blocks...

Here is a picture of the ground strap. Notice that when I received the car as a restoration project, the copper braided ground strap was connected from the valve cover to the wiper motor. What a mess!

[Jim T.]

Re: I Knew I Knew Less About Big Blocks...

Matt I am the original owner of a 68 and 70 SB's and have not seen the ground strap connected from the wiper motor to the engine like in your picture. The wiper motor from what I can tell in the service manual has a ground wire that connects to the heater motor housing for a ground. Also in looking at my 70 owners manual it shows a different torque numbers for the LS7 and also different HP. The March 1970 publication of the supplement Service News has 490 for torque and my owners manual has 500 for both the 390HP and 465HP 454's. Should of looked at the owners manual before I posted earlier about this. It looks to me that you have a distributor without a vacuum advance in your 70. Are you going to drive it for pleasure or race it?