The Master Parts Catalog calls for part C5MY-6243720-A which is indicated as having been used on the 1965 Comet as well as the 1965 and 1966 Mercury. I recently managed to get one of these NOS. It’s 50-year-old rubber and therefore useless except that it illustrates the correct shape, as seen in the below picture:
Using that NOS part as a guide, I conclude that many of the parts houses are incorrectly tagging Dennis Carpenter D0AZ-6243720-A for use with the 1965 Comet, including Falcon Parts, Rubber the Right Way, C&G Ford, and Mac’s (however see below as Mac's is a real mess on this part...). (Steele Rubber also has its own [slightly different] version of this part numbered 20-0302-84). The shape of this part is well illustrated by Falcon Parts as follows:
[Note the contour of the sheet metal channel - this is not the same as my '65 Caliente (which instead looks much more like the below illustration)].
Not surprisingly, this was the part that came on my '65 Caliente (installed during a previous restoration). I recently tried to reinstall the part (as it is still in pretty good working order). It seemed correct in that it fits nicely into the trunk channel. However, even after extensive "break in," the seal worked havoc on my gaps and made getting a good latch closing nearly impossible. (This was also part of the reason I was having so much trouble installing an aftermarket powered release as per this thread).
As far as I can tell there is no exact reproduction of the NOS part. However Dennis Carpenter C3AZ-6243720-A is extremely close, arguably identical (and for all practical purposes "close enough"). I have held this part next to the NOS part and its essentially the same. The shape of this part is illustrated by the installation sheet found in the packaging as follows:
[The contour of this sheet metal channel is very similar - though not exactly the same - as my '65 Caliente.]
The only supplier I can find who has tagged this part for use with the 1965 Comet is Mac's , however Mac's also tags the above (IMHO incorrect) seal for the same car (so in my view Mac's is also a "fail" on this).
Otherwise the part is widely tagged for use on a variety of Mercury cars including the 1964 & 1967-1970 Comets (just not the 1965 which is, in my view, an error). Sources include Rubber The Right Way, Auto Krafters, and C&G Ford. (Interestingly Rock Auto, which I have found to be an extremely reliable source of correct parts, does not offer any trunk seal at all for the 1965 Comet...)
There are two additional parts that I recommend avoiding:
- First is Metro Moulded Parts TK5118 which is tagged for use on the 1965 Comet by Classic Industries. This part looks similar but I have held it in my hand and it is significantly different. IMHO this part does work better than the first seal I describe above (D0AZ-6243720-A) however it does not work as well as the one I recommend (C3AZ-6243720-A).
- Second is Steele Rubber Products 20-0095-84. Steele does not tag this for the 1965 Comet (though they do the 1964 Comet). Again this part looks similar however IMHO it is a poor facsimile - as it appears to be missing one of the ears that serves to hold the seal into the channel.
Note that the installation calls for use of weatherstrip adhesive however I am choosing to forgo that step (man I hate that stuff...). On my car the seal is firmly in place w/out the adhesive so I am gonna roll without it...