Identifying Parts

The fastback came with a lot of parts. Since the previous owner had owned it for a long time with many plans to make it a resto-mod, many of the parts are from various vehicles from a variety of years.  I figure I would start taking some inventory to identify just what I have here.


The original doors are still present, and the driver door has the door tag intact fortunately. This is great since Marti reports are not available for Mustangs older than 1967. The VIN matches the various stamped locations on the front clip as well, so everything is legit. It also decodes to a 65 Fastback built in Metuchen, NJ. It came with a 289 v2 engine, and it was the 13143 Mustang off the line since this plant started at 130000.

Other than the fastback, it was a pretty plain car. Standard black interior, Springtime yellow exterior. It was targeted for build completion on March 22, 1965 to be delivered to the New York sales office. It had a C4 automatic transmission in front of a 2.80:1 conventional rear end.


The steering box is an easy one with a tag readily accessible. The original steering box is very similar to the 67. Having decoded that one previously, this one was pretty easy. I am confident this is the original since it still has the original steering linkage attached to it as well. The tag confirms it. Checking the decoder reveals its a disappointing 19/1 ratio 65/66. I didn’t expect it, but I was hoping for a 16/1 ratio. It was manufactured on December 28, 1964. I probably won’t put this back in, but I can figure out the plan for that later.


The original rear end still has it’s data plate as well. Decoding it here, this appears to be a 7 3/4 inch rear, not an 8 like I thought. I guess that explains the odd tapered tubes down near the drums. As the door plate says, this confirms it is a 2.80 gear ratio. The date should be in March 1965, but the B stumps me.


The newer engine was more difficult. I had a hard time figuring out just what this casting stamp was supposed to be. Piecing things together, I think it is F3SE. F3 would be a 93, which makes sense from other areas on the engine. The S is a bit of a surprise as that’s a Thunderbird, and E is an engine.


Under the casting for the part number, you can see the casting for the date. This is easier to read as 3D20. This supports the 93 since it starts with a 3 for the year. D is April and 20 is the 20th. So, April 20 1993.


The last piece of evidence here is the serial number. P is 1993 based on this page I found. Doing a bit more digging, the F here indicates Dearborn, where they were only making Mustangs. I found the Thunderbird was made in 3 different plants. With serial numbers starting at 100000, this must be 178868. It’s at least a 5.0L HO from a 93 mustang. While it would be nice to think it was from a Cobra, I found a plate from the intake that said 5.0 HO, where the Cobra would have said Cobra.


The last piece to sort out is the modern rear end. It already has the disk brakes on it, but it also has different mount points, so it will require fabrication to go onto a classic Mustang with leaf springs. It’s also a few inches wider. The tag indicates it’s a 3.27 ratio 7.5 inch rear, probably from a ’89 mustang with a V6.

This is all a little tedius, but it’s a good start to understanding what I am starting with. I am pretty excited about the engine as it’s what everyone seems to be looking for in a resto-mod. I need to figure out some of the other parts just to clear out the garage some, if for no other reason. I still have a ton of small parts in boxes to go through as well.

Next, I need to start cleaning up the frame to get ready for blasting and sheet metal repairs.

UPDATE 3/25/18:

I had some questions about the rear end which caused me to do some more research. It seems even though the numbers are 7.75 by the chart, they are still referred to as a Ford 8 inch rear end. This explains why I have only heard of the 7.5 inch 4 lug from the 6 cylinder and the 8 inch 5 lug for the V-8s.


While I was digging, I found the casting date for the differential housing, which supports the fact that it was original with a Jan 29 ’65 date. I like seeing the original orange there too, like I see in many of the restoration project pictures.


Another thing I thought was odd was the tapered axle tubes. The ’69 8 inch in the ’67 are not tapered. I haven’t figured out what the deal is with that yet.

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