[dplidr@gmail.com]

I found similar blocked bottoms on some of the stud holes in my block. Must all my studs had at least 6-8 threads remaining. A few had only 4-5 left and were corroded. I found out that all the studs do continue thru to the water jacket, however the ones close to the threaded mounting holes on the side of the block (for the coil etc.) did bottom out fairly quickly. I carefully poked the few blocked ones with an awl and then gently drilled open with a slow progression of bits. Finally chased all the threaded holes in the entire block with the right-sized tap to clean up for the old studs and a few new ones. The glass-bead blasting did further open up a few water passage areas I thought were metal.

Will take/post a few pics later this weekend...

-DaveL