You can buy 3M Scotchbrite style pads and a mandrel for cleaning mating surfaces. Chuck it in a cordless drill and get to it. Works great. You will have to use a shop vac to vacuum out the cylinders after cleaning the block. Usually I stuff rags in where I can to keep things clean. Use clean rags to wipe the cylinder walls with some light oil until the rags do not pick up any dirt.
You need to spread some RTV at the front and rear where the lower manifold seals to the block. Do this just prior to installing the LIM, you don't want it to skin over prior to. You will be supplied with cork but it is a very common mod to use RTV. Black is what I use. I have used it on 302's and the 4.0L successfully.
You should allow the RTV to cure prior to staring the engine. If you start it right away you might mess up the seal if there is a strong enough vacuum in the crankcase. Probably not, but for the sake of a few hours... let it harden up over night.
