Solid mounts

Um, those suggestions are for biscuit mounts- the OP said he has spool mounts?
Check with Prothane
Prothane Motor Mount Kit - Black : 4-504BL (pitstopusa.com)
Prothane 4-504 Chrysler/Dodge/Plymouth Car Motor Mounts | eBay
Not aware of any steel inserts.
The solid biscuit mounts can only be used if you change to the earlier K member and motor mount brackets.