Here's a double whammy question for the group.

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Robnbama

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On the lower part of the fender towards the front of the fender bolt hole directly behind the wheel I cannot find anything to bolt the fender to. I'm sure there's something missing. I could Google it and search for days and days but I know somebody here could tell me exactly what it is. The second one is the neutral safety switch on this C6 transmission is missing. I know the transmission came out of a 1973 Ford F-350 truck which is mated to a 460. My question is when I go to order the neutral safety switch do I order it for a 73 Mustang or a 73 Ford f-350? I know I'm going to run into a wiring nightmare if I have to get it for a F-350. Any and all help would be appreciated!3A55B926-7427-4957-A863-75FB21611A0A.jpeg 4C06C7B8-1AD5-4810-914A-1549F8CDEC32.jpeg
 
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There is supposed to be a tab on the pinch weld/rocker with a speed nut to bolt the fender to. The NSS for a 1971 429 Mustang was located on the shifter inside the car. I don't know about the 1973 Pickup. Good luck. Chuck

Bob beat me to it while I was typing.
 

Robnbama

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Thanks for the input. I’ll look into the shifter tomorrow to see if that’s where it’s hopefully located. My Mustang is a 1973 and came with the 351 two barrel carburetor.
 
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Hello Robnbama,
I've had discussions with some forum members who have found neutral safety switches (NSS) located at two different locations on '71 429 C6 Mustangs. I checked a microfiche catalog from 6/71, and only one NSS for a '71 Mustang C6 is listed, DØZZ-7A247-B. I checked my Mercury info, which shows the same part # for the '71 429 C6 Cougar. This switch is mounted at the manual shift arm location on the transmission.
These are mass-produced vehicles from the '70s, so variances (either by design or accident) and "Things" happen. Some devout Mopar and GM friends tell me their brands are just as bad as Ford's with these issues. I've dealt with these numbers for many years and still get shocked at some of the things I see.
I have also heard from some original 429 C6 owners who found the NSS at the shifter. This is the same neutral safety switch/harness as the FMX utilizes. Since your '73 started life as an H code 351, it was more than likely equipped with an FMX transmission, although on a smaller scale, some were equipped with a C6. If you don't see wiring where one may have been located on the transmission, pull the shifter cover/bezel and look for a tape tag with one of the following engineering ID #s, C8ZP-A, C9ZA-C, D, D1ZA-AA (Part # C9ZZ-7A247-C). D2ZZ-7A247-B (Motorcraft SW-1148) replaced the C9ZZ-C switch. This switch and others you see listed after 12/1/71 incorporate an extra circuit and plug for the hated seat belt light/buzzer system. The '71 shop manual does have one reference to the neutral safety switch adjustment at the shifter for Mustang and Cougar with FMX or a C6 with a 429 engine! Other than the one reference in the '71 shop manual on the '71 429/C6 NSS adjustment at the shifter, I've seen nothing else that would indicate that the NSS was located anywhere other than the transmission.

The '73-77 C6 equipped F series (regardless of the engine) has a steering column-mounted NSS. There were some significant changes in the '78/F series, and relocating the NSS to the transmission was one of them. So I would stay away from the truck switch and wire harness.
And just for the sake of confusion, my '71 M code C6 Mach 1s (Early build 9/21/70 and late build 7/28/71) have neutral safety switches on the transmission.
This is one of those times I would sure like to corner an engineer from this era of cars and ask, What.....were you thinking!?

The nut/retainer shown below is representative of the Ford 379114-S2 that is cataloged for the '71-3 lower fender attachment. The Ford version is discontinued, but it is something you should be able to find locally. The size is 5-16"-18, and the part number for the AMK pictured version is B13529.
 

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Robnbama

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Hello Robnbama,
I've had discussions with some forum members who have found neutral safety switches (NSS) located at two different locations on '71 429 C6 Mustangs. I checked a microfiche catalog from 6/71, and only one NSS for a '71 Mustang C6 is listed, DØZZ-7A247-B. I checked my Mercury info, which shows the same part # for the '71 429 C6 Cougar. This switch is mounted at the manual shift arm location on the transmission.
These are mass-produced vehicles from the '70s, so variances (either by design or accident) and "Things" happen. Some devout Mopar and GM friends tell me their brands are just as bad as Ford's with these issues. I've dealt with these numbers for many years and still get shocked at some of the things I see.
I have also heard from some original 429 C6 owners who found the NSS at the shifter. This is the same neutral safety switch/harness as the FMX utilizes. Since your '73 started life as an H code 351, it was more than likely equipped with an FMX transmission, although on a smaller scale, some were equipped with a C6. If you don't see wiring where one may have been located on the transmission, pull the shifter cover/bezel and look for a tape tag with one of the following engineering ID #s, C8ZP-A, C9ZA-C, D, D1ZA-AA (Part # C9ZZ-7A247-C). D2ZZ-7A247-B (Motorcraft SW-1148) replaced the C9ZZ-C switch. This switch and others you see listed after 12/1/71 incorporate an extra circuit and plug for the hated seat belt light/buzzer system. The '71 shop manual does have one reference to the neutral safety switch adjustment at the shifter for Mustang and Cougar with FMX or a C6 with a 429 engine! Other than the one reference in the '71 shop manual on the '71 429/C6 NSS adjustment at the shifter, I've seen nothing else that would indicate that the NSS was located anywhere other than the transmission.

The '73-77 C6 equipped F series (regardless of the engine) has a steering column-mounted NSS. There were some significant changes in the '78/F series, and relocating the NSS to the transmission was one of them. So I would stay away from the truck switch and wire harness.
And just for the sake of confusion, my '71 M code C6 Mach 1s (Early build 9/21/70 and late build 7/28/71) have neutral safety switches on the transmission.
This is one of those times I would sure like to corner an engineer from this era of cars and ask, What.....were you thinking!?

The nut/retainer shown below is representative of the Ford 379114-S2 that is cataloged for the '71-3 lower fender attachment. The Ford version is discontinued, but it is something you should be able to find locally. The size is 5-16"-18, and the part number for the AMK pictured version is B13529.
Steve you are a lifesaver. That is exactly the info I was needing. I was so confused before but now it all makes sense. I think I can tackle this on my own now. Thank you!
 

Robnbama

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Here is a picture of the lower fender mounting points on my car and a picture of the label on the box of j nuts that I used. with the part number and specs.
Hopefully it helps

View attachment 69941 View attachment 69942
Now I see what I’m missing. It’s the small steel platform that is welded onto the upper panel above the pinch weld. The nut retainer slides over this. I can definitely rig something up similar to that. Time to break out the welder! Thank you!
 
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My all time favorite vehicle is our 1969 Shelby GT500
In 1973 the Neutral Safety Switch in the Mustang had 6 wires going to it, not 4 as in prior years. The one pair of wires that is new in 1973 was used for the Seartbelt Interlock device that was largely disconnected by the dealers and independent repair shops (legally) as those early Interlock systems tended to not work properly, and/or caused significant issues for folks. The Interlock wires are:

Circuit 469 Light Green
Circuit 520 Purple White Hash

i have one relatively small schematic showing the Neutral Safety/Backup Light/Seatbelt Interlock Switch circuitry for 1973 Mustangs. I have additional schematics, and some video clips, that are too large to attach to this post. I have uploaded all those "other" files to my Google Drive, and said files are located at the following web address (Google Drive address below). There is a lot of information overlap in the various schematics PDF files, but if I recall correctly there were enough differences for me to keep them all, and I never bothered to create a hybrid PDF to cover all the information between them.


I hope the info in the files is helpful as you work through your NSS issue. For the record, I have always seen the NSS mounted to the side of a transmission, never in the shifter housing. But, I have no doubt there are plenty of floor shifter mounted NSS units out there. Luckily they are fairly easy to adjust. And replace.
 

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