http://www.galaxydrill.com/drillsiz.htm
you will need to know the spec on the thread of the bolts.....
I most definitely do not just bolt the two plates together dry, it'l leake like a siv in that fashion..... there can only be GOOP.
but be careful with GOOP... it sticks like shit. you are going to have a real hard time getting the block open, once it's cured. the best way to pop it, is the use the tap, and screw it all the way into one of the fitting-threads, then just gently tighten, until it pops open, once that's done you can get a knive in and work the rest..... but for doing just from the side.... forget it... you are just going to ruine the side of your block....