70 TA

As far as I know GM no longer has a production 5.7L engine and this new 5.3L casting takes its place having sleeves that can be finished for either bore size.

I first heard about this here on LS1Tech (the search feature doesn't work very well these days so I cant find it) and there is enough material in the sleeve for the 3.90 bore size, apparently the block was designed this way, you know keeping production costs down.

So for now as far as new GM blocks, as far as I know you will be seeing blocks with 5.3L and 6.0L cast in the back of the block with the 7.0L soon to follow

Also as far as I know all 5.3L engines are aluminum block now and there is no longer an iron 5.3L production engine from GM.

StickSS

Thanks for the info Camaro Joe. This is what I thought that GM was doing. If all the new truck motors are alum. the there will be a lot more good cheap core motors out there. This might be a good way to go for alot of people.

70 TA

Actually I was wrong a bit, it looks like there is a high output 5.3L for the trucks which is aluminum and there is still an iron 5.3L but I'm pretty sure the other info is correct.

I wonder though how much longer Iron 5.3L and Iron 6.0L blocks will be produced with the LS2 6.0L aluminum block having what looks like some provision for DOD cast into the block.

PREDATOR-Z

Why doesn't anybody believe me???

Nick Agostino

Hi Matt, the new 5.3 bare blocks we buy from GM are identical to a 2001 ZO6 block except for 2 things; the bore is smaller (5.3 stock) and the material behind the sleeves is a bit thicker as well. These blocks also lend themselves as a better choice for a 427 re-sleeved engine as they have the bay to bay breathing (ZO6) and the extra material behind the sleeve gives better cylinderwall stability.

The identical shortblock you have (block and all) was in Mighty Mouses car for a few years and made over 800rwhp with no issues Ask dave how reliable the shortblock was, he actually came in with a cracked cylinderwall ( 5.7 block) and we replaced it with a 5.3.

These blocks cost us a bit more to but but are more reliable and this is what we have been selling for the past year as a 5.7 as someone mentioned this is the replacement for the 5.7 anyway.

I will " RE-SEND" the engine build sheet over to you today, not sure why you didn't recieve it? I know it was sent. I will call after it is sent just to follow up and answer any other questions on the engine.

technical

Can you bore these 5.3 engines .13" over? That seems a little extreme...

Nick Agostino

The 5.3 blocks alum. or steel can be bored to 3.900 no problem ( sonic testing is manditory ) We have done many with no isues. The cast 5.3/4.8 block has just as much wall thickness as the 6.0 (steel) after it is bored to 3.900

technical

With new sleeves correct?

zamboxl

iTrader: (1)

so is this only on new 5.3 litter alum blocks (meaning after the 5.7 was faced out) or all 5.3 lsx alum blocks are the same.

technical

I don't think there was a 5.3 Al block before. It's new because GM is now putting Al 5.3 engines in the Monte SS, and the Impala SS, Grand Prix GXP and some trucks.

zamboxl

iTrader: (1)

wow they started putting v8's in the monte well they might be wprth looking at, now if they only fix that litle front wheel drive problem.

01Blackerado

iTrader: (4)

The 5.3l Aluminum block was introduced first in the SSR. From 99-02 the 5.3 blocks that came in the gmc sierra and chevy silvy were iron blocks. The best way to tell them apart is that the 5.3 iron block and the 4.8 are the exact same block just different internals( rod length, crank), and the block says 5.3/4.8 on it!!!!!! Since this one says 5.3 only on it its probably the aluminum block 5.3. I have also heard that broing these out above 3.903 is very unstable however when done in the iron block it holds stable!! You can bore the iron block 5.3 out to 3.903 at max and throw in a 4.00 crank with 6.125 rods and obtain a 383iron small block!!!

Nick Agostino

Hey Matt, the fax was sent yesterday and need a note back confirming you recieved it,

Thanks