I have a freshly rebuilt 400 short block, that I got for free. I am thinking of putting Vortec heads and vortec style manifold on it. I am not trying to build a high horsepower motor, but would like more torque than the tired 305 I have now. I am trying to keep costs low and don't want to use aluminum heads. I like the fact that the heads come preassembled. I know I will have to drill the steam holes, Does any any body have a procedure for that?