get one of those lil cameras and look thru the spark plug hole..


and like they said look at the crank..

and correction, the 4.8s are also an aluminum block.

So like nonnie said.. hope they're an honest person. When I sell my 4.8 Ill even show them the vin on my truck to verify if they want. I kinda got screwed on my 6.0 but Im getting it taken care of

Take a screwdriver and stick it in the spark plug hole and feel the piston. Start at the edge and go across. If you feel it dip after about a 1/2 inch it's a 5.3. If it never dips then it's a 4.8

They never made a 4.8 aluminum block; they did make a 5.3 aluminum block though.

You could look for the VIN of the truck the engine came out of........other than that.......pull the heads.

Pulling the heads wouldn't always work. I though some of the later iron 5.3's were flat top as well 06-up??? Pull the pan look at the crank to be sure if you don't have the VIN.

X2 no aluminum 4.8's

most of the time their is a mark on what ever the motor is like a circle are a slash throught the number the block is.i really don't think anyone will be able to just pull a oil pan and look at the motor and say oh yea it is a 4.8 are yes it is a 5.3.

if you pull the heads you could measure the stroke pretty easily. best way to tell.

+1 :nod:

How much oil can you fill the cylinder with? That'll tell ya the volume of the cylinder and which motor yer dealing with..............