400 block casting flaw
 

I had a buddy give me a complete long block and notice the flaw in the rear of the lifter valley
Is this going to be a problem

Having had a lifter valley failure I would not run that. At least not as is. Maybe a mega brace?

No, not an issue. Actually fairly common.

That's a hard picture to see what's going on. I can't tell if I'm seeing damage or shadows. It may be worth a quick trip to an engine shop and see what they have to say.

is that not the area that has the hole cast in the pass rear side lifter area that takes oil down to the dizzY?Tom

The flaw is the oval shaped hole center back lifter valleybetween the last two lifters

Don’t listen to 64speed!

Many a block that I have had in street cars and race cars have had that.

Just grind It out some so that

1) a crack can’t start.

2) so that the real thin section can not break off when in use.

I have a 67 400 block out of my 67 F with less than 10k it looks just like that. I agree with Steve. I'd be leary about a high lift aftermarket cam though. Inspect for cracks,like a spray, around that area just to be sure.

I see the oil hole to the left and above the flaw.Tom

Better safe than sorry. My bad if I’m giving someone advice on an abundance of caution. It’s my opinion and just my opinion that I would get a mega brace

Is fine. Is a typical procedure to Grind the thin stuff away.

As others have said. This is just a variation in the casting pour. Like HIS said, grind the thin stuff away. Just like the flashing at the opening below the lifter bores. My 421 block had a similar imperfection. Cleaned up and it was not an issue.

This.

Seen a few like this and it’s not a structural issue, just a minor casting flaw.

Good to go
 

Thanks for the replies I will look at getting the block tanked and checked then debur??

Run it, I've seen dozens of blocks with that casting flash in the same area. I've never saw one lead to catastrophic failure in a street engine, or a race engine. This flash is not in a critical area that would lead to a fracture.

This same subject has come up previously on this forum, the consensus has always been, grind it off if you're concerned about it, but there are likely hundreds of engines running fine with the flash intact.

Years ago while working in a Pontiac dealership I witnessed a 4 bolt main RA IV block that had bad porosity in the main caps under the bearing bores while in for warranty work. It looked like termite holes in the caps. I wouldn't have trusted those caps, especially on a high output engine. They put new bearings in the engine, and sent it back to the owner, never heard or saw the car again, likely the engine ran for many miles with those porous main caps. That cast iron is tougher than you think it is, back in the day engineers designed parts like these with plenty of excess strength margin.

The excess engineered strength in these blocks is the reason a 2 bolt block will withstand 600 HP.

Same here. Making almost 1400hp with a block that started out with the same blemish. Very common.

When you take the block for its bath have the shop touch that up if you do not have a grinding Burr and power tool to deal with it.

It’s so common that if you’ve got a 1974 shop manual in section 6-75 … you can see the same inclusion printed right there in black and white.

I'd be more concerned about the rust in the lifter bores.

I had the same thing on my 400. No big deal