Sonic checking my 71 360 block

33IMP said
To do a sonic properly....
Check the cylinder at 0°, 90, 180, and 270, at the top of the cylinder, middle, and bottom, and write down the numbers.....
then do it seven more times.

It does sound like your block is pretty good.

I will tackle this tomorrow and report back with he numbers. Where I found that .177 number as at 45 degrees and 2" down the bore