Is it true that .....

[Longhorn Man]

high nickle blocks have a little more nickle in the iron than a normal block, and they don't wear nearly as fast. I took apart a caddy big block (they were all high nickle) that had a tad over 100K on the clock, and there was not only no ridge at the top of the cylinder, but you could actually see a little bit of the cross hatch from 100,000 miles ago.
that 300,000 mile (never rebuilt) 350 did have some ridge, but the pistons still came out the top by hand with no ridge reamer needed.
On chevy engines, high nickle blocks can be ID'd by seeing 10 and 20 under the timing chain IIRC. In my opinion, high nickle is WAY more important than 4 bolt mains.