Tiger, I used to work at a machine shop (I did dissasembly and reassembly of engines) I learned alot about the trade. Even if the machinist could fix that crack which would require tig welding to fill the crack and some light machining to resurface. the heat produced would traslate into other parts of the engine It is only cast aluminum. After any major welding was done on a block (we only did this if the engine was rare) a full machine was done to the engine to ensure the block was in check. So in reality to repair that engine properly would cost the price of 3 new GMS .32 or more.

Here is a link to the new block for that engine it's only $20. If tower can't do an exchange or replacement the repair is very simple
and straight forward. to replace the block is the same procedure as replacing the bearings which you will need to learn to do some day.

http://www2.towerhobbies.com/cgi-bin...?&I=LXEGP8&P=Z : link to crank case.