Will a Mustang instrument cluster and dash inserts fit in a 67 Cougar?
no
It can be done it’s just a lot of work. The dash frame is a weld in piece and would have to be modified as would the wiring harness modifications. Here is a picture.
Steven
Why climb the mountain? Because it is there. Go figure.
Thanks for the photo 67 S code. Personally I like
it and the cost is the driver here. Is there any details of what needs to be modified?
As you can see the present condition is in progress and mods can be easily done. Wiring is not an issue. Just need to know how to modify the dash.
Good news: the outer two air conditioning vents will not be effected. Everything else changes. You just cut the Cougar dash out, cut out the steel part of the Mustang dash, weld it in, and then buy ever part of a Mustang dash: easy peasy.
Soooooo, xr7g428. You have done this? Thanks for the encouragement.
Nope, I parted a car that had been converted. It took me a while to figure out what I was looking at as the dash pad was missing and most of the fascia. Both cars share the fire wall and everything that hangs on on it. The heater boxes and all are the same. The center AC vent mounts differently. The out board mounts are the same.
I can see one wanting a cougar dash in a mustang.
Thank you all for your input. Sorry to all the purist folks but double the price for Cougar parts vs Mustang? 
This is a restmod that I am just glad I saved it from the recycler. Just to give you some background info. I picked up this totally disassembled 67 Cougar and most of the parts needed replacement either due to wear or missing. (3) previous owners thought it would be nice to have a project car and after those failed attempts I picked it. I looked into the cost and compared the gauge layouts and prefer the Mustang individual gauges so why not install them? So if anyone has any first hand experience with this conversion, I would greatly appreciate any helpful insights.
The sheet metal body structure of the Cougar dash is all the same as Mustang. There is a speaker support spot welded across the center of the Cougar dash structure that needs to be removed. After that it’s all identical.
You would not necessarily have to replace all the wiring harnesses if you are clever enough to read a wiring schematic. Slight wiring mods and you could use any of the available Mustang instruments.