My cleaing method on a block, normally first is a caustic washing, this could be in a hot caustic vat, or soft caustic spray cabinet, your machine shop with have them, if it's cam bearing block like the A series engine, for hot caustic dip, they have to removed, on the 1500 there is no cam bearings stock, so you don't have to worry about that on that engine. Galley plugs should be remove, so especially the one that run down the edge of the block into the fornt and back side of the block, and I replace brass plugs with taper NPT plugs, and that should all be done before the block cleaning process due to the tapping and debris that causes . After the intial caustic cleaner, I normally have few things left to do the block, maybe even machine work like boring, the caustic wash for me is the first degreasing cleaning and by no means the last cleaning of the block, final cleaning for me, is a hot water and degreaser cleaing while the bare block is on the egnine stand with a garden hose, when I ddi this at home I just used the hot water connection at the washing machine and hook a garden hose to it and did this outside, using engine brushes to get inside all the oiling orfices and make sure they were clean using spray nozzle on the hose, that had a spray slection on it to flush out all orfices on the block including all the water jackets as well. Then after finishing this final cleaning I would use compressed to blow it dry quickly, then spray WD 40 on machine areas of the block like the bores and main crank saddles, then once it is dry and lubed in the appropriate areas, I use a large plastic garbage bag to cover the engine while work is not being done to it, to keep it clean from dust. Hope this helps.