[DFBonnett]

Originally Posted by atn1kjm

The mechanic and I discussed the possibility of Helicoiling the existing screws, there isn’t enough room between the water jacket and the block for them to fit.

Before I accepted the mechanics word as gospel, I'd check with tech people at ++ TIME-SERT Threaded inserts for stripped threads, threaded inserts, thread repair stripped sparkplug's, Ford sparkplug blowouts, threaded inserts threaded, repair stripped threads, stripped threads, inserts threaded inserts, Ford spark plug repair, and
Heli-Coil ( HeliCoil Inserts ) Helicoils Screw Thread Inserts | Emhart.com

They may have specific application information of which your mechanic may be unaware.
FWIW
YMMV