StorminMatt

It was always my understanding that the 2003 Escalade came with either the LM7 or LQ9 from the factory, both of which have cast iron blocks. Yet at the local Pick and Pull, there is a 2003 Escalade with an aluminum block. The bores look larger than a 5.3. So it is DEFINITELY not an L33 or LM4. But they look like they are probably smaller than a 6.0. Maybe a 5.7? The block also is most definitely a Gen III - it has knock sensors in the valley. And the heads are cathedral port (I didn’t have a bright flashlight to read the head code). But the big kicker is the aluminum block. I didn’t think this year came with one. Would this have to have been a swap?

theunderlord

If it is aluminum it would not have come in the 02-96 Escalade according to the definitive reference source. How many miles on the truck?

WhiteBird00

iTrader: (4)

Do the blocks change to aluminum after a certain number of miles? That's cool!

01FormulaTA

iTrader: (20)

Sounds like someone swapped in an LS1, an 01+ LS1 had the same cam and similar compression and could have been a drop in replacement with no tune required.....NBS Escalades only came with Iron blocks