4.8 cracked deck
 

Picked this up last year , the seller said it was a 2006 4.8 . Has the beefier internals so it is the newer style . Tore it down over the weekend . Cleaned up the pistons , gapped the rings to .025 . Was cleaning the deck , lo and behold the block is garbage .
https://cimg2.ibsrv.net/gimg/ls1tech...667a4ab5a7.jpg
https://cimg3.ibsrv.net/gimg/ls1tech...9b1afa0262.jpg
https://cimg4.ibsrv.net/gimg/ls1tech...8e948472e8.jpg
https://cimg5.ibsrv.net/gimg/ls1tech...7d843b7376.jpg
Wonder what would have caused that . I have another 4.8 sitting around but its a '99 with the long crank and gen 3 internals . So I'll swap them over to the '99 block and go from there.

I think you are right , it did sit outside the exposed to the elements last winter , mind you it doesn't get that cold here 4-5 degrees below freezing at the most , but I guess thats all it takes , still bummed out about it .

I wonder if that can be carefully grinded out in a valley shape fairly deep and then Tig Welded to fill it back in? Then machine it flat?

I would still be concerned about cracks in places you can't see. This crack might not be the only one.....

Yeah don't think its worth the hassle or $$ to fix it , can pick up a bare 5.3 block for $100 . Plus I have another 4.8 sitting around .

^^^^^^^^ Wise thinking! You don't need the hassle....^^^^^^^^^^^

Was this an early block with graphite head gaskets? The etching looks terrible on that block, almost like it had leaking head gasket issues.

^^^^ This.

Freezing temps is all it takes.

And you're saying it only gets to the upper 20's in Vancouver BC?? It gets that cold or colder here in Texas...

28F is still freezing and WILL crack a block if the temp is that low long enough, like all night and part of the day

Came with MLS style head gaskets . I was cleaning it with a sanding block and 320 grit sand paper . You can see where the whole deck is recessed at cylinder #3,5,7 from it being cracked because sanding block didn't get the gasket material off . This what the other side looked like
https://cimg5.ibsrv.net/gimg/ls1tech...e047896480.jpg

I live pretty close to the water so , doesn't get that cold. There'll be that odd night where it'll get down to 5 degrees or so but that's about it , don't think it got that cold last year .

We have what's called a "maritime" climate here - the ocean keeps the temps very stable year round. Doesn't get very hot, doesn't get super cold.

I used to live in LA County, within about 12 miles of the beach. On average somewhat warmer than where you are, but still pretty stable temps. I DO miss that weather! But that's about it...

It's a 4.8. No sense whatsoever in spending money fixing that block. Just like it didn't used to make sense to spend money fixing a 305 block.

Throw it in the recycle bin and spend the pennies to put something w bigger bores in its place.

Just make a table out of it.

I was just curious, I don't typically see that much etching with MLS gaskets. Maybe they overheated it and filled it with water. Either way we all know its junk. Thanks for responding to my question.

Man i would take it off your hands to mock up turbo piping but it would probably cost out the ass to.ship.