I just need a small sample, about 1" by 1" square. Apparently shavings from drilling will work, but I'd rather not risk the drill bit coating or material contamination. When (if) pieces are obtained, I like to know as much as possible about the block. A lot of info can come from the suffix code, but block casting number, location of the "010" and/or "020" (above oil filter pad, under timing chain cover, at bellhousing mating surface, etc), 2 vs. 4 bolt, date code, and any other cast in letters/numbers are all appreciated. (instead of "010" you might see "089" in the bellhousing area for instance, although I made that number up. I've seen other numbers there.) Helps to ensure that any results will be indisputable based on year especially, since some people also believe that earlier blocks had better metal composition. Of course, only testing one year of a casting number won't tell the whole story, but if say two blocks from the late 60's are tested (one 010 and one not) and then a block from '79 without that is tested, you can probably rightly assume if the '79 block has less added material than either of the 60's blocks, GM got cheaper later on, which would be par for the course. I'm working on this for other GM blocks as well, Oldsmobile for instance is rumored to have had better material in their blocks than Chev (of course no proof there either) so I'm accepting samples from the 5 GM Divisions to have tested at the same time. Copied and pasted this as a response from another post, so to clarify, what I'm doing is trying to gather as many samples as possible, and send them off to a lab to get them tested. They will be looking for metal composition differences based on year and casting ID numbers, since these are the most common "myth's" (my word) surrounding GM engine block material. I ask that the sender eat the shipping to me (it's not much for such a small sample), and I'll eat the shipping cost of all the samples to the lab. It's been very hard to get people to actually send me samples. Lots of response typically, very little follow through, so don't expect to see lab results right away, unless somehow I get many samples quickly. This is normal of course, so I'm not chastising anyone thats been thinking about it, but hasn't got around to sending it in. I know how busy people are!