50adrod

iTrader: (1)

I am trying to make sure the motor I am looking at is definitley a 5.3. it is from a wrecked 2006 Tahoe and the number on the motor is 515SX6380776
is there a sure way to tell if it is a 5.3 and not a 4.8?

babydeuce

iTrader: (24)

Short of tearing it down, no real way to tell. Can you see the top of a piston? Flat top=4.8, dished=5.3. Do you know what vehicle it came out of? Run the VIN

Jack

spikely23

iTrader: (1)

pull the oil pan and check the clearance from the crank to the windage tray, thats about the quickest way.

Steve68

iTrader: (23)

I think 5.3's say 5.3 on the block toward the rear, not sure, I read that, I can look at my 5.3 later,

50adrod

iTrader: (1)

no sure way to telll what it came out of, it is suppose to come from a 2006 tahoe. the person selling it bought it from a salvage company and never used it so all i have is the motor and trans sitting on the ground. it does have the harness and ECM any clues there. if i run the ECM part number would that tell me? the motor/trans looks nice with only 50 miles on it but I want to make sure I am buying a 5.3 and not a 4.8

50adrod

iTrader: (1)

what are the measurements? 5.3 vs 4.8 ? thanks

50adrod

iTrader: (1)

please do and let me know, someone also said the VIN is lasered on the head somewhere, is this true? that would confirm for sure

Schwanke Engines

iTrader: (1)

It actually says 4.8L/5.3L on both the front and the back. The only ways to tell are to:
Look at the tops of the pistons, as already mentioned, and
Measure the stroke of the crank, as already mentioned.
A 4.8L has a 3.268" stroke, 5.3L is a 3.622" stroke.
The difference is made up in the rod. The 5.3L has a 6.100" rod and the 4.8L has a 6.267".

Eurospec2

iTrader: (2)

As Schwanke said, the block is stamped 4.8/5.3 on the front and the back. GM identified them with a paint splotch on the corrosponding number, but if the motor is old/nasty/greasy, it may be hard to see.

If your certain the PCM is the original PCM with the motor, it could be read to see if it has a 4.8 or 5.3 cal inside of it, otherwise the hardware for the pcm is the same for both.

50adrod

iTrader: (1)

thanks for the input, but please tell me where to look for 5.3 stamped on the engine. on the block or heads ?

Schwanke Engines

iTrader: (1)

It is actually cast into the block on the drivers front and the passengers rear.

50adrod

iTrader: (1)

thanks for all your info. one more question how big are the numbers cast in the block? and would I have to remove anything to see them? I have a 5.3 in a truck at work and was going to see if I could locate the marks

Schwanke Engines

iTrader: (1)

You would not be able to see them unless you take the alt/ps bracket off, or removed the trans from the back.

50adrod

iTrader: (1)

thanks again, it sould not be to hard to remove the alt/ps bracket considering it is out of the vehicle. would you happen to have a pic of the casting marks? I know I am asking alot.

Schwanke Engines

iTrader: (1)

Trust me, you won't miss them when you see them.

50adrod

iTrader: (1)

for those that know here is a picture of the block driverside behind the alt/ps bracket . 5.3 or 4.8 ?

spikely23

iTrader: (1)

ive seen a few 4.8 and 5.3 engines the paint always seems to be wishy washy as to which motor it is, if u pull the pan the crank is pretty close to the windage tray on the 5.3 while the 4.8 has almost a half inch more clearance

GMade03

i did a little home work and found that on the 17 digit vin# (found on dash visible from windsheild) the 8th digit is the engine code, in the 1500 2wd the letter V=4.8, T=5.3 and U=6.0