Hey guys dumb question here. How do I figure out what kind of short block I have? LS1s are an aluminum block but the one I have is definitely iron. Is there an easy look at this code on the side of this to tell what kind of block it is? BTW it has LS everything else, intake, heads, etc.

 

theres acasting bnumber on the back of the block on the drivers side. plus numbers like 5.3 or 6.0 embossed on the sides of the block

 

There is a code 04K01 just in front of the passenger side head. As for looking in the other areas I will have to wait until daylight. Btw thanks for the help 01 Vert!!!