Clean and detail the engine compartment. Consider new motor mounts, there are a couple of options to go there. Ground relocation so you don't have that PITA attachment at the p/s head. I don't know why you have the engine out, but if your rear main seal is leaking, it's way easier to do on an engine stand. While you're doing the front cover, there are oiling improvements possible. Lou Czarnota drills out the oil passages in the cover. A Melling oil pump with HD spring *used* to be de rigor, but some people now say that the stock oil system is fine.