If your looking for a rubber gasket these ones fit and work fine with my chrome OEM style covers.

https://www.edelbrock.com/valve-cover-gasket-set-for-ford-7568.html

Thanks for the update. I've waited months for interior parts for the Cougar. Gave me extra time to research and refine other aspects of the restoration. Guess you've been staging as much as possible during the wait.

Here's a nice clip that gets into some of the nitty gritty about bore vs stroke. Kind of a tangent but.... A different perspective on things too. Generalization are sometimes the pitfall of a project but I totally get how those old wives tales make there way into shop talk.

https://youtu.be/UV3RwBPqznU

Thanks for the confirmation and suggestions. As suspected - This pan of mine has some history. Probably as you describe, it was crushed upward and repair attempted.  It was about 1/4" up in the worst spots. Totally obvious with a straight edge but not severe enough to draw major attention to itself. At least not to my eyes. I noticed the scratches on the edges but didn't get alarmed until seeing the insides.

I was able to reclaim that 1/4" and the local auto parts store had the correct filter screen in stock. New pan gasket is also more than twice as thick as original. Should have plenty of clearance now. Also flattened the gasket surface. Took the pan bolts up to 6 ft-lbs. (About half the OEM Spec.) Any more seems to much. Performed the refill procedure per the manual. No leaks thus far. Around 8 to 10 quarts is when I could feel the trans engage gears. Will take it for a gentle drive tomorrow and bring the fluid level to the full mark when completely warmed up.

UPDATE 8/8/20 - The Moroso reusable gasket combine with my old pan was horrible. The old pan is a softer metal and the bolts (no washers) started to pull through and basically ripped the gasket to shreds. Major leaks etc.... Tightening just made it worse. I pulled the pan and used a thin rubber gasket that came with the filter. I flattened the lip of the pan and used Gasgacinch on the pan-to-gasket surface. Transmission to gasket was dry. Was able to add washers to the bolts with the thin gasket. No leaks now thankfully.

Hi All - Need some support on C6 transmission filter variations between 2WD and 4WD. About a year ago I bought this Mercury and was told it had a “new” transmission.  I think I found a 4WD filter jammed into a 2WD trans/pan? Trans was quirky from day 1. It was overfilled with fluid when I bought it. I figured they knew something I didn't... Now I think it was restricting flow, possible cavitation on a normal (shallow) pan. Took forever to switch from Park to Reverse or Park to Drive. Recently the fluid smelled burnt so I decided to change it.  This seems to be a 4WD filter from a late model C6. 1975-1996. From some quick searches it would seem I have a 2WD version of the C6 as my speedometer cable is connected normally.  Think I read that 4WD versions have the speedometer cable in the transfer case. It's a D servo with an aluminum tail shaft. Pan looks stock. Everything is bolted up but I have not added any fluid. Didn't want to waist any if I have to pull the pan again.

The old filter has some suspicious dents and deformation on the pick-up side. I don't have a picture (yet) but I did notice an outline similar to the shape of the pickup on the bottom of the pan. Almost like a kiss-mark.

The filter I have looks different but bolts up fine. As the whole valve body is submerged in fluid I think this is correct. Need to bounce it off some folks that have seen a few of these though. I took a picture showing the drain plug on the torque converter but the valve body is in the background. Plug was in this position when I pulled the cover so everything was going well until I stared questioning the filter.

Well I hope you guys are right as that would be good news. I'd like to keep this engine running as long as possible until I get a more stout replacement prepared. Thanks for the belt removal suggestion.

How the aftermarket fan aligns with the shroud has to have a big effect also. This assumes you are running with a shroud. So the spacer/clutch depth needed to be considered. (As well as rotating direction. )

As an aside I just put back a factor 7 blade fan and Thermo clutch. It replaced an autoparts store plastic fan. Not a flex fan in the true sense. Cars not been out on a hot day yet but I could immediately tell the engine had less vibrations. The old fan was just a low quality item.

Great to see things are coming along. I am waiting on car parts too but for the interior rather then engine. So I understand the pain of waiting. Good luck with the build and test!