HG parts

[IHateHacks]

No dude you used a die grinder with a wire wheel which is about the worst thing you can hit the block surface with next to 100 grit sandpaper. Not good. Now you might need the block surfaced professionally. That sealing surface is the most important sealing surface on the engine.

I used a 90 degree angle grinder with an attachment on it for 3M pads. There are many different abrasivnesses but I used the one meant for aluminum, so I was good. You just don't want to stay in one spot too long or use too much pressure or spin the tool too high of rpms.