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Discussion Starter · #1 ·
When I bought my '66 SS I didn't notice that my backup lights didn't work. Later I discovered that there was no backup switch on the Muncie M-20. I now have the switch with wiring harness and extension harness. From the assembly manual it appears that the wiring harness and the extension harness join together at the firewall at a penetration just above the steering column.

When I look at the firewall I don't see any location in that area that is pre-punched for the wiring. However, there is a rubber plug in a hole that appears to be the correct diameter (~1") about 6" below the steering column. Is that the correct hole? Or ???

Thanks!
Greg
 

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Greg,

That hole is used for the speedo cable on automatic transmissions. The correct location is about 6" in (towards engine) & 2" up from where the master cylinder connects to the firewall.

Mike Sibbitt
66 396 SS
 

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Here is were the hole is located on my 67 convertible, I believe a 66 would be in the same place.
Firewall
Hope this helps.

------------------
Ken<UL TYPE=SQUARE><LI>Aces # 125<LI>Team Chevelle # 586[/list]My 67 and other projects



[This message has been edited by KEN67RAT (edited 02-24-2001).]
 

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Discussion Starter · #4 ·
Ken, your great pix shows a hole just as Mike described it. Unfortunately, my firewall doesn't have a hole there.
Does your '67 have the hole for the speedo cable for the automatic transmission? If it doesn't, I'm thinking that Chevrolet used different firewalls for 4-speeds and automatics. ??? That doesn't seem likely. But if so, maybe my car was originally an automatic that was converted to a four speed.

Greg
 

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Greg, for 67 the hole below the steering column was used for 3-speed, automatic, and Saginaw 4-speed transmissions. For Muncie 4-speed transmission a plug was put in that hole and another hole was drilled in the firewall on the passengers side. Since your car had a plug there , it could have been an original 4-speed. There are a couple of more things to check this. First what is on the bottom line of your cowl tag? An L after the number 2, is the code for a 4-speed. An M after the number 2 is for a powerglide trans. Also look at the steering column, it should not have any shift arms on it if it had a 4-speed(but floor shift transmissions had no arms also).
If your speedometer cable exits on the passenger side, it should have the hole in the firewall for the backup light harness, but I suppose that someone could have moved the speedometer cable.
If you want exact dimensions, I can get them for you.



[This message has been edited by KEN67RAT (edited 02-24-2001).]
 

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Discussion Starter · #6 ·
Thanks for the feedback Ken. I've been working on the yard and the car all day and have packed it up for the night. I'll check it out tomorrow.

Greg
 
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