89 L98 roller block (350ci)
Was looking for a 10 or 20 to see if this block had tin or nickel. I didn't see the numbers. Did find a 627 and a G-12. What do these stand for?

 

627?? Are you sure? What's the casting number?

According to www.Mortec.com.... 627 is a 305.
14093627...305...87-91...2...Roller cam, one-piece rear seal

I hope I'm wrong and you do really have a 350, but it doesn't look like it.

The other number/letter might be the date it was cast? I dunno though. Last I knew, the "G" would be July, but I don't know what the "12" would be? If it's the year, normally it's a single digit like an "8", which could be 1968, 78, 88, or 98, but I don't know of a "12". Sorry

Go to that www.Mortec.com and compare your casting number to their list to make sure you have a 350 and not a 305.

 

It's a 350. Motor is stripped. 4" bore
casting number is 638.

I was taliking specifically about under the timing chain cover.
Didn't think about date codes and such. I'll check on that.
Really just want to know if this block has tin or nickel in it. Guess not.

 

The casting likely contains both tin and nickel, as well as a little copper, manganese, zinc, chromium, and traces of other metals. What you are probably interested in is the level of nickel content. The "high nickel" castings are certainly more prized. Unfortunately, I don't know what mold marks identify those parts, but the main part casting nubers usually lend some hint as to the type of casting. some of the marks are simply mold core markings that may not have a lot of meaning outside the foundry or mold shop.