Ok, buddy that smashed up his truck a bit ago....FINALLY got the block from him. Casting 880, 4 bolt mains, 1 pc rear main seal, roller cam. checks out all fine and dandy, good to go. So i ask him about the cylinder heads. He says "sure have them, i dont think theyre good though..." So i take them, look at them, theres a funny green spot on the head. i have NO clue what it is. I dont want to waste money on hot tank/magnafluxing if a crack is visually detectable.

 

Got a pic thats closer to the problem area?

It might just be some of that paint that junkyards use to mark their parts. Post a close up pic and people will be able to tell you a little better if it's a cracked head or not.

 

i don't think the greeen paint relates to a crack. have it pressure tested it be sure. or find someone to dye pen it for you.

 

It's possible that it could be from leaking around the studs, or cracked stud bosses. But it looks like it would have to be 2 of them, which isn't all that likely.

I'd agree with ede though, when in doubt, just get them checked.

If it turns out it's the studs themselves that leaked, a set of screw-ins would fix it nicely.

 

I think the most common place to crack is around the ports particularly the exhaust ports. I'd pull the valves and clean it up really good and then inspect the ports and combustion chambers very closely. I won't say it isn't possible, but I would be very surprised to see a crack on the valve spring side of a head.