tips for cleaning block surface
 

Are there any tips for cleaning the old head gasket material off of the block surface without a bunch of crud falling into the engine oil and coolant passages? Or does it matter?

Hold a shop vac right in front of your razor blade as you scrape. Once you're done, blast whatever you missed out of the holes/passages with an air compressor.

I have started plugging up those holes with bits of shop towel to stop debris from going down all the holes. Definitely chase out all the head bolt holes and also find a really good straight edge to check for warpage of the block surface. After you are done with the block, you can pick the plugs out of all the holes and start blowing everything out with compressed air.

The cylinder heads are in the machine shop. The machinist told me I could use maroon scothbrite to clean the block surface. I’ve read so many opinions against that though. Because of all the fine dust that the pads will make.

It will do that. The shop towel bits will catch most of the dust. I tape between the pistons and cylinder walls also and use a piece of granite slab with fine sandpaper to get everything flat and clean. Good luck with it!

Be careful about plugging holes, lest you fail to unplug or can't retrieve. Vacuum is good idea. Razor blade scraper & some gasket softener like PB blaster, etc (can't buy real effective stuff w/methylene chloride anymore). I personally will not use any abrasive like sandpaper, emery cloth, Scotch brite etc. around engines, gears, bearings etc