What are the differences found between the old 5.7 blocks to the 6.1 blocks? I have 4 blocks, 2 are 2004 and 2'are 2006 i have not completed a total sonic check yet. I was just wondering what people have been using for 600 HP plus builds, and whats the difference between a 5.7 and 6.1. Just trying to figure out if going to a 4inch bore is an option.

Max Weg

I've wanted to do this, but we don't have a small enough UT probe to check the blocks...

I am going to shape mine to the bore and buy a new probe for larger bores.

Max Weg

Please post your numbers when done.

My 6.1 block at 4.08 bore

thanks for the 6.1 info I have shaped a probe and completed the block but just need to verify before I post the results.

Max Weg

Keep in mind that these blocks have higher nickel content than the La blocks of old.
Imo they are stronger with less wall. To a certain degree.
Matt

i have the test results, I just need to figure out how to post them from an Iphone.

Max Weg

Allegedly, early 5.7 blocks (03-05?) are supposed to be a heavier casting, but I've never seen #'s to back it up

This is the results from a 2006 5.7 block which will be good for a 392 build but not for a 410.

Max Weg

That's pretty beefy, you could probably go to a 4" bore? It would put a couple of spots at .150"ish but that's still thicker than the 6.1 than sixpackgut posted

http://nutterracingengines.com/

These guys recently had a 5.7 block for sale that was 4.060 bore and had sonic numbers showing .130 as the thinnest spot, said they have done numerous 5.7 blocks that way and yet to find one that couldn't safely go 4.060

Music to my ears, have two 06 5.7. One swapped valve seats tore up cylinder walls. Thought about 4.0 bore but 4.30 even better. Cheaper SB Chevy and Ford pistons with infinite deck heights. Plus lower priced rods,off the shelf. Don't have to put up with the Dodge weird sizing. Look at the many options on bearings,rings, rods too.

https://seattle.craigslist.org/see/pts/5393449881.html

Looks like they've got another one for sale. I talked to them about one they had for sale a while back and they said they do it all the time and they always sonic check as good or better than a 6.1

That's not a bad deal, ready to go block with pistons and rings for $1500.