68 Quarter Extension research; conv. vs fstbk.

[68blk500c]

Recent parts inquiries, and persistent past topics, continue to call out different quarter end caps as being unique to either the convertible or fastback.  Documentation submitted here says they are all the same.  I agree that there are very minor variations to the trunk spoiler area, but those may be due to different molds.  Please add other documentation that supports otherwise:

 

[Coralsnake]

I think this the case. The same goes fir upper and lower scoops, I suspect it was mold differences

[Coralsnake]

Heres is one being sold as convertible but box numbers are clearly the sane as parts listing above "63"

https://www.ebay.com/itm/306177715465?_skw=nos+shelby+end+cap&itmmeta=01KDNG26CMBQJP2T5DX0FJ3BQ3&hash=item47499d2d09:g:UwkAAeSwC5Rnyd6C&itmprp=enc%3AAQAKAAAA8FkggFvd1GGDu0w3yXCmi1ekBHoq8qfP8BD1n8S2iW40Ce1KicH08EwVSSaq6f4Tq7JTEV3wMsV1zD7Di2JmoxZF8Velozjx%2Fl4w%2B2ob6pXeF3uoWQ1klMnjVWWYFQQv8jln0IxBun0uac3YoINzCTmW8R87OqyaMcuZEZvh63HrMXw8HNDJ5dF9IpWuuVzkDPtvsfxB7c5eqGkOJgzlU99U01Lr%2BwcelV3sx3f%2BR2qs%2FeOvYGbImAwLPoF1lu9KxIPmEoS0HUEXweILF6GLp4LwgVT%2B30ZjVGxWJqz27Drg0JgffT1JYVCZ1j0%2BG6yHTg%3D%3D%7Ctkp%3ABk9SR8DmiLDtZg

[Bill Collins]

My experience is that they are different. I have confirmed this by examination of various '68 Shelbys that I have sold. See photos attached. These are both original, formed from sheet moldable compound (smooth back side), as opposed to hand laid up fiberglass (chop glass back) reproductions. Sheet moldable compound was produced by Armstrong Industries for AO Smith. They used it to achieve more uniform tolerances, resulting in improved panel fit. See the photo for an illustration of this process.

Ford often combined part applications to streamline things in service, especially on lower volume items - e.g. Cobra Jet carbs C9AF-M (manual) and C9AF-N (automatic) were both serviced by C9AF-U (Universal).

The variation may have been present only in original production, and the styles were consolidated in service from the beginning. Thus, it is plausible to suspect that both styles were always serviced by one surviving part number.

Ford published OSI (Obsolete, superseded, interchanged) manuals in part to advise of such consolidations. Affected numbers were often noted "m/w" (mixed with) "r/b" (replaced by), etc.

[68blk500c]

My experience is that they are different. I have confirmed this by examination of various '68 Shelbys that I have sold. See photos attached. These are both original, formed from sheet molding compound (smooth back side), as opposed to hand laid up fiberglass (chop glass back) reproductions. Sheet molding compound was produced by Armstrong Industries for AO Smith. They used it to achieve more uniform tolerances, resulting in improved panel fit. See the photo for an illustration of this process.

Ford often combined part applications to streamline things in service, especially on lower volume items - e.g. Cobra Jet carbs C9AF-M (manual) and C9AF-N (automatic) were both serviced by C9AF-U (Universal).

Ford published OSI (Obsolete, superseded, interchanged) manuals in part to advise of such consolidations. Affected numbers were often noted "m/w" (mixed with) "r/b" (replaced by), etc. So, it is plausible to suspect that both end cap styles were serviced by one surviving part number.

The March 1968 date of the SA Parts Catalog documents means a superseded part happened DURING production, which I am doubtful happened, Bill.

[shelbymann1970]

Well I'll take my friend's convertible end caps for his 68 and see how they fit on my 68 FB or do a back to back comparison from my perfect pass side to his DS. I don't know but I know belt line reproduction sheet metal for 68  coupe/vert is sold as diff from FB by aftermarket companies and one well known guy told me there is slight differences on the contour of a Vert to a FB and he is wealth of knowledge. NPD sells one and says modify for convertible or GT/CS(coupe). So I will test fit my friend's vert end caps on my FB when I can get them so it will be a few days at least. NPD says slight modification. So I don't know where they got that from if not true? Their FB version fits fine on my 68 but prefer to use an original if I can find one in time.

[Coralsnake]

My understanding is SMC is a product used after AO Smith developed FRP - fiberglas reinforced plastic.

I havent heard the connection with the Armstrong company

http://www.thecoralsnake.com/FRP.html

[68blk500c]

My experience is they fit the quarter panel the same.  The only difference is what is shown in Bill's photos.
I have not heard of the variation causing fitment issues with the trunk lid.
Recent observation of several 68s did not reveal a distinct pattern; some end caps matched; others varied. 
No way of knowing, for certain, which may have changed out over the years.
Just looking for other DOCUMENTATION to separate fact from fiction.

[Bill Collins]

My understanding is SMC is a product used after AO Smith developed FRP - fiberglas reinforced plastic.

I havent heard the connection with the Armstrong company

http://www.thecoralsnake.com/FRP.html

Pete,
Many years ago I purchased some '69 Shelby fiberglass from Ron Charney. Included were some side scoops and unfinished components such as underhood reinforcements. He told me he found them at the Detroit area Armstrong plant. From that, I surmised that they did the '68 parts as well, but that may not be the case.
Bill

[Coralsnake]

I am not doubting you, just hoping to add to the knowledge base

[Bill Collins]

There are two words I have disciplined myself over the years to not use when discussing most things Shelby: "Always" and "Never".

When what is offered is anecdotal, the vagaries of one's personal recollections are always a factor.

[Coralsnake]

Another reported NOS for the discussion

https://www.ebay.com/itm/236548441684?_skw=nos+shelby&itmmeta=01KDP7NZ38KND4RGM6EGQANTX7&hash=item371362c654%3Ag%3ALIYAAOSwaxZm8%7EnW&itmprp=enc%3AAQAKAAAA8FkggFvd1GGDu0w3yXCmi1cUnDxY9PpqAuAAvUicCWfesVgG6Wivnkn3v0GdUncsnw44tM92G1unBgzPpKjXYv7HcVsKAzk63tDjFqSCSwRxeiOMeTB0%2BDziqa4klBI9tspk%2BuTmj%2Fycfj9PZBBJSpw0m2nQO4ldXod6o1%2BKSY9NNcmpnx2JAYizVHDKBKfT%2FOeqQru9UA7TNhD56WHe1Cm%2B9XlJNoG3oTs1OEqHa91yjFoIghPLMv3efD8PzKwf%2BZIVXwBjx0NltEbKydLOveclmjZO5Gl3AKRgZFx9ID0kUw5e1DU5NB6Iib5WlQfZ3w%3D%3D%7Ctkp%3ABk9SR_bx18ftZg&keyword=nos+shelby&sacat=0&relatedSearch=true

[shelbymann1970]

Well I got a pair of original ones off my friends disassembled 68 GT350 vert and hopefully tomorrow morning I'll be "fitting" them on my FB to see and will compare my pass FB to my friends pass vert ones. Personally I hope they are the same as it opens up more options to finding a DS end cap for my 68 FB. BTW my friend's car was built first week of March so I assume AO Smith a short time after and the end caps still had the silicone on the edges so am assuming original to the car as it is a red car and no other hint of another color. .

[shelbymann1970]

So here are the convertible ones off my friends March 68 vert mounted in my FB. Fit like a glove and the pass side is identical to my FB one. So I will double check these pieces that came off my friends vert that they indeed fit  his vert as I never seen them on the car before he took them off. .should have done that when I picked them up last night.

[shelbymann1970]

Comparison of the 2 right sides