Welcome to the forum, Dawson!
1981's had a clutch linkage, instead of hydraulics.
These parts are rare as hens teeth.
And those pedal supports do not interchange between them and the '83/'84-> trucks that have hydraulics.
Do you want synchro 1st?
What is the diff ratio in your truck?
So, you're going to need a transmission hump pan and shifter boot.
You'll likely want a manual shift steering column and a blanking plate for your cluster as well.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.