just a general thought on block heaters. When installing a block heater the ideal location is going to be a casting, freeze, frost plug located between cylinders,
not one in line with a cylinder. My engine had a threaded 1"npt plug that I could remove to install the block heater. And some one trying to remove a freeze plug by drilling it out?
To drill a hole into a freeze plug and the use a screw to remove said plug is a common way, think about it people, a freeze plug is less then an eight of an inch, to continue drilling
and go thru a block and a sleeve into a cylinder that's a **** of a lot of drilling.