This is a 400 block for sale. Here are the bore numbers. How does this look to you guys? I am trying to learn to see if it is worth building.

Thanks

What is the bottom number on #6 on the outside of that cylinder?
If it is above.200 I would be glad to use it in a heartbeat
How far are you wanting to bore it out to,+.030,+.040, +.060 or what size?

Thanks Cab. I don't know what that number is. Best guess is .456 but I don't think that makes sense.

This was e-mailed to me and it is the best pic I have at the moment.

I would bore this out as little as possible.

Not that i’m experienced enough with sonic testing or owning a large sample of blocks, but can those numbers be right?? I’ve never heard of bore thickness in the .600” range. Or even .500”+ for that matter within a stock block. I could be totally off base, but i thought some of the afternarket blocks are proud to have .300”+.

Why no readings for the thrust face on #2?

For what it's worth, those numbers appear to me to be large by a factor of two.
The machine or the operator recorded doubled values ?

Just my humble opinion.... these numbers seem too good to be true.

I can tell you there are double what the 400 that was in my daughters 76,D100 are

I wouldn't touch this unless seller agrees to a sonic test, and he eats it if the block falls below usable limits. If it passes, you pay for sonic check, all negotiable anyway.

If something appears too good to be true. Don't trust it! I would take the block somewhere else and have it checked. Exact same thing happened to me. Had a block sonic checked and numbers were really good. Had it bored to 4.400 assembled the motor. But didn't install, I came across a good deal on a KB solid low deck. So I sold the short block to a guy in Cal.. Months later I got a call from the guy . He had the motor dynoed and it blew up on the dyno. The cylinder walls were paper thin. Lesson to be learned, if you have a block sonic checked. Make sure the equipment they are using is of top quality, not chinese junk. If it checks out too good to be true. Don't use it.

i don't think the tester was calibrated correctly. pie in the sky numbers.

Something is not right, the theoretical max wall thickness between 2 adjacent cylinders would be .458 if siamese, the sum of the wall thicknesses on several adjacent cylinders is higher than .458

Thank you all for confirming my suspicions. This is a " 230" cold weather block 400. The one with the huge main saddles. I was looking at this last night online and could not believe the numbers, but I am not an expert so I thought I would ask here.

I bought a early casting cold weather 400 block from AndyF, he had it sonic tested and I retested it with my Dakota 1000 tester, the thinnest place on the worst cylinder wall was .167 down low
The thickest was around .350, that block clean up at 4.350 and was still running good after 5 years of running it in my S/P car on E85 with no top end lube

The numbers are thicker than a World block....

I don't want to be negative...so I'd say...Hey, anything is possible!

Except that...that isn't

Absolutely not good numbers at all. Either they are fake, or someone doesnt know how to calibrate their sonic tester. You first do whats called a " probe zero", then you calibrate it to a known and measurable thickness.