Go to your local Pick-n-Pull and grab a Mustang 5-speed driveshaft and tranny x-member. The TC pedal assembly will work. The TC has a plate at the base of the steering column that mounts the slave cylinder, IIRC. Don't get rid of your TC donor until the Mustang is completed. You'll constantly find stuff you can use or adapt, not to mention a ton of the correct fasteners!
Last year I sold a complete conversion assembly out of my '88 TC parts car. The guy was gonna swap it into a Mustang. Here's pics of all the parts that you need

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Trust in the Lord with all your heart and lean not on your own understanding.
Proverbs 3:5
1989 Mustang convertible w/built and turbo'd 2.3.