yo R,
maybe others can assist you with this info;
Rear Cover Assembly; aka Automatic Transmission to Engine Spacer Plate
1993 Bronco/Econoline/F-Series Workshop Manual by Ford
https://www.motorcraftservice.com/pubs/content/~WSPM/~MUS~LEN/21/SPMLEFT.HTM
Section 03-01B: Engines, 5.0L MFI V-8, 5.8L MFI W-V-8 and 5.8L MFI Lightning W-V-8
1993 Bronco/Econoline/F-Series Workshop Manual
REMOVAL AND INSTALLATION
Flywheel
Removal
- On a vehicle with a manual transmission, remove the transmission and flywheel housing, clutch pressure plate and disc. Refer to Group 08. On a vehicle with an automatic transmission, remove the transmission and converter housing. Refer to Group 07.
- To check flywheel face runout or to replace a flywheel ring gear for a manual transmission, refer to Section 03-00.
- Remove the flywheel attaching bolts and remove the flywheel.
Installation
- Coat the threads of the flywheel attaching bolts with oil-resistant Threadlock and Sealer E0AZ-19554-AA (ESE-M4G204-A-Type II) or equivalent. Position the flywheel on the crankshaft ******. Install and tighten the bolts in sequence across from each other to 102-115 Nm (75-85 ft-lb).
- On a vehicle with a manual transmission, check the flywheel runout. Section 03-00. Install the clutch pressure plate, disc and the transmission and flywheel housing. Refer to Group 08. On a vehicle with an automatic transmission, check the flywheel runout. Refer to Section 03-00. Install the transmission and converter housing. Refer to Group 07.
https://www.motorcraftservice.com/pubs/content/~WSPM/~MUS~LEN/21/SPM31B26.HTM
Try to read through the engine section for any seal or sealing material used on the spacer or flywheel
Some other info from WWW;
Mark has also noticed that a good number of these plates have a strip of either cork or weatherstripping-like rubber along the bottom edge, perhaps to provide a seal and to help keep rattling noises down
http://www.428cobrajet.org/id-trans-spacer