My buddy got a new LS6 crate engine in his 01 SS, so I was going to use his stock shortblock for 1 of my projects. But, upon inspection I saw 2 cracks in the block, one on each side. They are both in head bolt bosses. Normally I would guess that somebody didnt clean the head bolts, but there is no indication the heads have ever been off this engine. Anybody seen cracks like this before? Not sure I should use this block now.

 

i wouldnt use it

 

I don't see any cracks. Just some casting marks that look like cracks.

 

could be casting flaws. you could always take it to a machine shop and have it inspected though. if they are cracks dont use it

 

They are cracks, not casting flaws. The second crack does not show up in the pics well at all, but you can see the first one good. All that red is the crack detection stuff I used at work.

 

I think it almost has to be from coolant in the head bolt holes. I bet someone has had them off. I would not use it.