Topic: Fender Bolt Head Markings for a Feb/March 66 built GT350

[ChrisV289]

Jeff I apologize if this should go into the standard 65-66 category or this one.  I'm looking to see what style of bolts/bolt heads were used on the inner fenders, engine bay, and spring covers on a 66 Hertz.  My dad replaced them with cad bolts a few years ago because they looked nicer but after seeing what I've done to my car he wants to go back to the stock look.  I believe the car was built around November/December of 65.  He is going to check on the sheet metal though.  I can send a PM of the Shelby VIN and possibly the Ford VIN as well.. 

[jwc66k]

The bolts are probably the same as my 66 Hardtop and 66 K Fastback both built mid October in San Jose: SEMS with two semi-circles around the SEMS, toothed dish, 378156-S2, 5/16-18X7/8 for most of the under hood bolts, fender, hood, etc - (difficult to get a total as some Shelby's did not use all the regular Mustang stuff); and the type with the head marking I call "Double Ditto", 378178-S2, 5/16-18X1.0, for the shields around the springs (officially called "Bracket, Upper A-Arm Bumper), 16 total.
Jim

[J_Speegle]

Changed the title to fully match the request

Will post some pictures of Mustangs from San Jose from that period. That's got to be a really low Shelby number and a very early Hertz. Engine bay is a tall order (lots of different bolts and such. Should be able to provide the majority. Quick look at one of my spreadsheets suggests flat washers on outer (fender) and inner (shock/spring cover) applications



Guess we're dealing with 6R120xxx-6R148xxx given your description. There were allot of Shelby's built at San Jose during that period. You can PM the Shelby and Ford VIN - leave off the last three of the Ford vin if you would like for security purposes if you would like

It's 1:30, time for bed - Yes I do that from time to time

[J_Speegle]

Having looked at the Ford vin you provided it appears IMHO that the car was likely built during the Feb-Mar 66 period at San Jose.  Corrected the thread title to reflect that

Looking at original cars around that same vin (Seem to have plenty in that range) I found the following examples/data

- Looking at a bunch of cars within five thousand vins lower and higher that the vast majority used flat washer bolts at both the inner (shock tower covers) and outer (fender) location. Have maybe 3 examples of start out of maybe 20 cars - for a ratio to give you an idea of why I would recommend the flat washer use

- Head markings included both the double hash "" and the SEMS

- Since you have a Shelby and that some of the shock tower bolts were removed at Shelby to install the Monte Carlo bar the forward upper bolts were rearranged when they were reinstalled. Since the bar requires an additional bolt being added it is normally of a different style. In your case I would expect a star washer bolt to have normally been installed in one of the two upper bolt holes (picture below.)

- Threw a few other bolts in to help out - Sorry haven't always taken clear closeups of head markings but we can go through specific locations rather than just blast a bunch of bolts up in one response

Hope this helps

6R171xxx



6R172xxx



6R173xxx




6R173xxxdifferent car from the one above




6R178xxx



6R1719xx Hood hinge



For the non-Shelby owners of cars from this period - the typical 23's



6S15xx original example

[ChrisV289]

Thanks Jeff.  I noticed on the last pic there is a bolt with a star washer holding the Monti Carlo Bar.  Is that random?  Looks like the safe bet would be the double tic marks since it falls within that 174xxx range.  BTW, car was shipped to Hertz mid/late March. 

[J_Speegle]

Thanks Jeff.  I noticed on the last pic there is a bolt with a star washer holding the Monti Carlo Bar.  Is that random?

Mentioned that earlier in that post. The use of a star washer bolt was typical for your period of time at Shelby. All three Mustang bolts were removed then replaced with the addition of one extra since they had to drill an additional hole forward for the bar. The start washer bolt could end up in any of the four holes but pictures of original cars show that typically it was one of the two top bolt holes is where it typically ended up from what I'm seeing

[Bob Gaines]

Mentioned that earlier in that post. The use of a star washer bolt was typical for your period of time at Shelby. All three Mustang bolts were removed then replaced with the addition of one extra since they had to drill an additional hole forward for the bar. The start washer bolt could end up in any of the four holes but pictures of original cars show that typically it was one of the two top bolt holes is where it typically ended up from what I'm seeing

To add- the star washer bolt ended up in the new hole more frequently then the other way around from my observations but as Jeff indicated the bolts were taken out so with out a protocol they could end up any which way. My preference is to replace the bolts as they were originally from Ford assembly and the star washer bolt in the new hole which would be the preference logically if there was a protocol. But that is just me.

[TLea]

One thing to consider regarding the bolt heads is often bolt heads are different because the length is different. A good example would be bottom fender bolt or bumper guard bolts. The July SJ car I just worked on had star washer bolts there that were the longer variety (1 1/8 vs 7/8). The star washer bolt came in both lengths used on same car. The disc washer I only found the 7/8"

[ChrisV289]

Jeff on the one pic with the hood hinge bolt attaching to the hood, would the same bolts be used to attach the hinge to the inner fender?

[J_Speegle]

Jeff on the one pic with the hood hinge bolt attaching to the hood, would the same bolts be used to attach the hinge to the inner fender?

Not ignoring your question and I assume that your asking about this specific time period and plant.  Going through pictures and not allot of clear pictures that show the fine details of washers and head markings and at first look a pattern has not stood out as of yet.   

[ChrisV289]

Thanks Jeff for your help. Those are the last ones he needs to change in the engine bay and we weren't sure which ones to go with. 

[jwc66k]

Take a look at the hinge (or other items, latch, shields, brackets, etc) to see what type of marks the previous bolt left, external tooth or disc tooth lock washer scratches. Time may be against you if the previous owner replaced the hardware with generic types.

- would the same bolts be used to attach the hinge to the inner fender?

These bolts were from different buckets (trays or some type of container) for each side, aka - two different assembly line operations, and the same applied to fenders (more than one operation per side), upper "A" arm bumper brackets (aka spring shields), bumpers and more.
The real question is what bolt types were used from hinge to hood as I believe Sheblys were shipped without hoods (as so many pictures show) and the hoods were installed at the Shelby facility. To expand this, there were three types (at least I believe) of hoods used on Shelbys.
In the Forum Library you will find drawings of head markings. From the drawings, types 20, 46 and 58 seem to be what was used in the San Jose plant at this time, with external tooth being phased out and disc tooth lock washer being phased in. They were mixed on many cars.
Jim

[ChrisV289]

Thanks Jim.  Unfortunately I'm not sure if we will be able to tell what was there before.  Owner before my dad restored the car and he had that Hertz plus another black and gold Hertz one that wasn't quite done yet plus a couple of other cars lying around.  So bolts could of gotten swapped.  Then my dad didn't like the way the bolts looked so he replaced all of them with cad bolts.  Now after seeing what I have been doing with the 65 fastback I got from him he decided maybe he should go back to what it "should" look like with the correct bolts

[J_Speegle]

Jeff on the one pic with the hood hinge bolt attaching to the hood, would the same bolts be used to attach the hinge to the inner fender?

Ok took some time and will mentioned this is from a very small sampling since we're looking at a specific period of time and a very limited number of cars and original (likely not changed) examples available. In addition the requirement that we have pictures of all four hardware points -  at least the goal.

So the direct answer "would the same bolts be used to attach the hinge to the inner fender' - They don't appear to be in my examples and often the two hinges (driver and passenger) are attached with two different types of bolts and washers.

Would also mention that I compared the hinge bolts to the inner fender bolts used on the spring covers and found those two applications don't match. Thought this (if they did) might suggest that both could have been installed at the same station but it didn't prove out

[ChrisV289]

It would be safe to assume these bolts are aftermarket that are currently holding the hinges on correct? Never seen this head marking