Ive got a 350 that was bored .030 over and i just began disassembling it today to put in a new cam and pistons. Me and a few friends didnt like the way some of the rod bearings looked (discoloration) so we pulled the mains off. A few of the main bearings had some grooves all the way through to the copper, so its time for some new bearings all around. Both of my buddies who have built engines before didnt like the way a few of the cylinders looked either, they said it looked like it had sat for so long the pistons left permanent marks and some edges you can catch your nail on from sitting for so long and to be safe they would have it bored out a little more to make em clean. So im considering boring it out .030 again to 4.060. Since ive never really done this my questions are, is this a safe bore? (i assume it probably is), and what will that make the motor?? (before with .030 it was a 355 with a .060 what is it?) Thanks for the help in advance!
Oh and i forgot after pulling it today the crank looked to be a stock 350 GM cast crank.

I believe 60 over is a 359. Most chevy block can be cut 60 over. What is the casting number of the block?

If going to bore it out .060 over have it sonic tested for cylinder wall thickness be fore any thing is done as we find a lot of blocks that would not be safe at .060 and have good ring seal to make power,

360 cubic inch, The other option is to go .040 over

Sounds like the oil filter bypass was not plug and you were not using a NAPA gold 1061 filter.

bore squared x stroke x .7854 x no of cyl's = cu. in.

4.060 x 4.060 x 3.48 x .7854 x 8 = 360.4227 cubic inches.

plus one,,, do .040 if possible.

I would recoment a hone and new rings if possible. Hone the worst hole and see if it will clean up. IF not, go .040 over.

Give it a 10-15 second hone job and see how it looks. 3-stone hone in a heavy duty drill, moving constantly up and down the bore as you run it. You only want to knock off the crud- not take any real metal off of it. Now if it's still got the lines on it or you have a noticable "ridge" at the top of the bore where the top ring stops at TDC it's time for an overbore. It's worth a shot before you drop money into a bore job.