i got a new donor engine for my friends' s-10. it's a 350, one peice rear main. I can't find a casting number, just says "5.7L G" on the back by the bellhousing. Also we were wondering about the possibility of resleeving the cylinders and how much it sould cost, because the block has a slight crack in #3. it was supposedly a marine racing engine and it fed coolant off the lake, the guy that owned it never drained it over the winter and cracked the cylinder right there. Any idea what engine we have? never seen one w/o a casting number.

 

There's usually three big digits on the side of the block. I have a 638 (last three of 14093638), which according to www.mortec.com .........

That's the most typical 350 block used in those years (exc. the LT1).

A cylinder can be sleeved if it's not TOO bad. You'll have to take it to a very experienced machinist and get a quote. By the time you pay to have that done, along with the other machine work, it may be cheaper to buy a new bare block.