I need to cut a (long) slit in a masonry wall, to fit roof flashing. The
wall is solid cement blocks. (No cores.) I've done this before with a
borrowed (7") angle grinder, which has since moved away. So, I'm
looking for one of my very own.

Lowes has a 7" dewalt grinder; but, it's rated 12 amp. Most that I see
on factory web sites (well, Milwaukee and Dewalt) are rated 15 amp. This
makes me suspect that the Lowes one is maybe not-so-great quality - just
a 'named' label on a Harbor Freight product.

Any thoughts or information on this would be appreciated.

Thanks.