Just noticed some cracks in my block the other day after taking it out of the car. It's filled with hard block above the freeze plugs and these cracks are just below that area. I think they've been there for a while. Do I have a potential problem. My machinist guy says "Run it".

Another shot.

One more.

If it's just a feeze crack (appears so) and it's filled, I doubt you'll have any problems. That being said, it's just a 440 block I'd pitch it and start over if it's a fresh build, it's not like a decent 440 core is big bucks or anything.

If the cracks are below the grout line, they shouldn't give you too much trouble. I would clean it up, JB weld or Marine-Tek it(to prevent minor seepage), and let it fly.

MB

What were your plans for it, race or driver? A driver can be a quick fix and just put enough fix to drive it. If your gonna go for some horsepower, just dump the block and get another one.

It's a race car only. 512 stroker on alcohol. It's been 9.99 and now running mid 10's all the time. I'm pretty sure it's been cracked for some time and I just now noticed it.

I'd run it too
If you don't have coolant in the oil it's not cracked internally, that would be my concern.
We've been running a "Non filled" 440 block 500 cu in. engine for years that has some cracks I ground and filled with JB weld not a problem. I did put a 7 lb cap on the radiator to keep the pressure down. No problem over heating.
I'd keep my eyes open for a replacement block for the next time you need some machine work done to that block and replace it then.

Hey guys, I really appreciate the replies. Feels good to know I can get some straight answers. Not like some other sites where everyone likes to be a smart a#s. I'm considering the JB weld idea. Thanks again.

Never been much of a fan for JB weld. I fixed a harley shovelhead case with that epoxy stick that you kneed up to mix. I think I had the only shovelhead harley in the state that DIDNT leak oil after that..