Pezzo33,
This is not a bad thing. This is an opourtunity!
The 258 was junk. I believe the primary reason AMC has left this planet is due in large part to the 258.
Run, do not walk to your nearest wrecking yard and aquire a GM350
Rebuild it strong, rebuilt it well. Add performance mods as you see fit.
THEN,
drop it in your Jeep. Live long and prosper. Be happy and content all the rest of the days of you're life.
!