Has anyone sonic checked their cast iron block (6L) at stock bore to see what the wall thickness was before the bore? How thick was it? The reason for the question is my local builder (whom builds all kinds of engines, not just LSX) test two different blocks for two different 408 builds, each were ordered one year appart. Both blocks found at least once cyl that only had 0.081" minumal wallthickness. Both were new blocks that had yet to be bored out. Just wanting to know if this is comin in the 6L cast iron blocks.

Thanks.

 

I remember something about the old 6.0l blocks but I thought it was known to get them magnafluxed when choosing a block?
FWIW I run a 6.0l 4.030" bore.

 

The last block was purchased this summer.

 

Here's the data sheet from the sonic test of my block before it was bored and honed to 4.031". There are some areas that are thinner than I would like, but they are on the fore or aft sides of the cylinders, not the thrust sides.

This was a used block probably built in 1999 or 2000 or so. None of the bores were larger than about 4.003", so wear was negligible. Also, I called some of the more reputable sponsors shops and they said that it was common to get at least a couple of cylinders that were thinner than desirable. One shop told me that they really didn't like to go more that 4.010" bore if the customer was going to push the engine hard with power adders. I plan to run my engine normally aspirated. I'm going for more torque more than anything and I feel comfortable with the block.

One note to consider: I was advised by a reputable shop that builds a lot of LS based engines to have my machine shop take several small cuts with the boring bar and let the block cool adequately between pases so that the bore didn't distort due to heat with the relatively thin sides. I passed this on to the machine shop and that is what they did.

Steve