IBM AT power supply case/cooling question

I'm using the case from an IBM AT to build a socket 7 Linux machine. The AT wasn't complete, and the case is a little rusty on it's hood, so it wasn't a good example to restore to original. My question is this..... can I safely leave the PS cover off? If I add a few of the factory screws the PS case/chassis is still quite solid, it just does have the cover on the top, or by the drives. Basically, it removes two out of six sides. I'd want to do this for a bit more cooling, since the fan would have less obstruction. Plus, I think it looks lind of cool too :-) Would I have problems with EMF emmisions effecting the computer's operations? The main case cover would be installed.... would I have other EMF troubles, if I leave the top of the PS off? Chad Fernandez Michigan, USA