[Lated]

I second the WD-40. I sprayed it on all the machined surfaces of my 350 and then put an engine bag from summit on it. The block had just barely started to rust before I put the WD-40 on it but I haven't noticed any new rust since then and it's been sitting for more than a year and I rubbed the rusty spots with a clean rag after I'd sprayed the block and it all came off. I've heard of people "pickling" their blocks by just leaving them out in the backyard unprotected. Supposedly a thin coat of rust actually protects the metal (but from what) but personally I'd rather just prevent the rust in the first place.