I just removed the high velocity water pump from my car's 350 engine. The block is a GM Mexican 350 Crate block. My issue is this. When I loosened the driver's side lower water pump bolt, antifreeze came out until the block drained. Once I removed the water pump, just to see if I was dreaming, I took a Phillips small shank screw driver and placed it in the hole, it went through the casting into the water port. This is not the passenger side, where there are thee holes for the water pump connection, two for bolts, 1 for free flow for I'm assuming the heater hose route. The passenger side lower and upper threaded bolt holes were only about 3/8 to 1/2" deep, the driver side upper is the same as the passenger side upper and lower, but the lower bolt hole goes all the way through the casting which is at this point about 1/2" thick. Is this standard? And if so, what do I use to prevent water seepage up the threads to the water pump housing and on out past the end of the bolt?