Over the years we have sold many of these bolts to people so they could safely put their engine on a stand. We decided to combine two of the most common sizes to make it convenient for anyone that regularly does rebuilds. You will receive four M10x1.5x100 (3.93") and four M12x1.75x105 (4.13") class 10.9 (approx. equivalent to U.S.grade 8) hex head bolts. These will work on many U.S. and European blocks and the length should be right for most engine stands. 
We are able to confirm that the M10 bolts in this set WILL work on Chevrolet LS engines.
Unfortunately we don't have an exact list of every engine these will work on, so please verify these are correct before you have the engine up in the air.