Formulation of AMC cast iron

I worked with 2 machine shops here as well as a machine shop in my home town (the fellow son happened to be my HS metal shop teacher!)
I have asked - especially the one local shop that did my last 2 AMC blocks. I asked them as they have a wall full photos of vehicles with AMC engines they have done, they have a long history with Jeeps.
They got this look like what the heck was I talking about....... no, they said they could never tell any difference.
You can find reference on the web to Ford racing engines and some here and there about Chevy racing engines. Apparently it's confirmed that certain Ford engines did up the nickle content, but not across the board for all production engines.
I have yet to find any shop that will even say "we think so" on AMC engines being "different" or harder. Even the shop that cut the 390 for me to install sleeves..... "not a problem, it's just like any other block we do" (I asked as at that time I, too, was questioning the content of those blocks.)
And I'm talking about the old-timers my age or older, not youngsters in newer shops with modern equipment and tools. Some of their tooling is as old as I am.
I've bored a few AMC 6s myself back in the 70s, using the Kent-Moore tools we had from when it was a dealership. I never noted any differences or difficulties. These tools I refer to came out of the late 50s. I have piston pin reamers and other dealer tools and equipment for working on those old engines - never a problem.
I've run ridge-reamers through over the decades, including "cheap" ones and they cut the AMC block material just like any other block. (gotta be careful with those things or you can screw up a block as easily as saving it)

We need to find someone who has other motors information. It be a good start for comparison and then we need to find someone who can tell us how to accurately compare the info.

Class Guy wrote: From the AMC blueprints for the 951 casting 401 block. This may not be applicable to the rest of the AMC engine line.

Cool idea, but the subtle differences from differing metalurgy and heat treat

What you're doing is just the kind of data I'd like to see.  I've heard that different castings of the same block can vary in hardness/tensile strength due to many factors.  The only way to get solid info would be to send samples from many blocks to be tested, but I'm not suggesting you or anyone do this.  Even checking one will maybe give you a real-life representation of the differences.  Thanks!

I've had many engines machined and have used the same machinist on all my engines. He mentioned to me years ago that AMC, International and some chevy performance blocks were harder on his boring bar bits then other engines. he did mention nickle and the grade of iron in the blocks. It doesn't take much  nickle to make a better formula for casting, too much and then you have concerns with heat dissapation and other concerns. oh and it gets real expensive.