Right above the middle two cylinders, looks like this on BOTH sides.

 

clean it up really good to determine. also whats the history on the block?

they have a spray that you can use the welders use it to determine the cracks. it sprays purple an the crack shows white

 

^^^^ The paint is a dye penetrate. Hard to tell if they are cracks, could be cast marks but shouldn't be there as that area is milled/decked for flatness. Was this a running engine? Def needs to be cleaned up to tell for sure.

 

I have a block that is cracking across like that around the cylinder jug between the water jacket holes. It looks identical to that. My machinist buddy figured it was no big deal to fix by pinning it. I decided against using the block though for that reason. I am not sure whether I would repair it or not. I had no history on the block that I had like that so I don't know what happened to it previously.

 

any suggestions on how to clean it? I have used everything short of scotchbrite pads. lacquer thinner, gasket remover, razors, and WD-40.

block has around 200k. guy i bought it off of said it was a running engine, just remembered it had a new water pump on it. the guy i bought it off of said it likely was ran hot

 

luckily the guy i bouhgt it off of sales them all the time, he said i could bring it back and swap out for another one. was just wanting to make sure that it was cracked and not something that is common in these motors lol

 

I wouldn't say its common. I have a few blocks and its the only except for yours now that I have seen do this. I might have it pinned and just build it as a naturally aspirated engine... or use it as an anchor lol.

 

i plan on boosting mine one day, but im def gonna swap the blocks out now. just wanted to make sure it was for sure a crack.

 

It looks like a crack to me. I'd get the dye to be sure, or have your local machine shop check it for you.