I suggest that you don't do this. Nothing good will come from it, will likely ruin or make worse the top ring seal, and could ruin the block. Probably the worst tool ever made.
The ridge is approximately .002 to .005.
If I dont use the reamer will it hurt the new rings that I put on the stock pistons when the engine is running?
What grit should I use on the cylinders for cast iron rings? [/quote
No it wont hurt the rings, the ridge is there because the cylinder is worn down and the ridge is where the rings didnt touch.As long as the stroke and pistons are the same it will not touch the ridge.
