It's going to be a PITA to try to port the heads with a Dremel. It's a good idea to get matched valve springs for the cam you end up getting, as the stock valves will most likely be worn out and soft from ~35 years of use. As far as the torque converter goes, the stock one is around 2200 RPM for a 318. Mind you your stall will increase a bit when you increase the torque from the engine. I don't think you'd really need to play with it unless you were making the engine a little more wild.