How can I tell the differense between 5.3 and a 4.8 liter LS motors

[Slow Build]

I'm looking at a few LS motors that are already pulled at some auto dismantlers. How can I tell if it's a 5.3 or a 4.8?

[VA72C10]

I'm sure others will be much more help but I know most if not all have it stamped on them if they are already pulled you should be able to see the stamping...

[suspect]

i'm not aware of a way to tell visually. i think the only difference is the stroke length. i'm sure they would give you hard time, but is it possible to take the intake and a head off to measure the stroke?

[cableguy0]

As far as I remember the designation is stamped into the block. Also if it still has the airbox attached which it should the emissions sticker will tell you.

[DjS71]

If I recall, the block for the 5.3/4.8 is the same. It'll even say "4.8/5.3" on the block. If you can't pull a head / oil pan or get a VIN, make sure you buy it for a price that is reasonable for a 4.8. Just to cover your butt.

[dwcsr]

The 4.8/5.3 use the same block with the 4.8/5.3 designation cast into it.
The older 4.8 had dished pistons and the 5.3 flat tops prior to 2004 after 2004 they both had flat tops. The crank casting number is the only way to tell for sure or if you have the PCM get the vin and it will also tell you.

I was told that on the casting 4.8/5.3 on the front there should be a paint mark that covers either 4.8 or 5.3 and that is the way the factory new which was which on the line. It did on mine but it may not actually be correct, I only had one motor to check it on.

[Slow Build]

Originally Posted by dwcsr

I was told that on the casting 4.8/5.3 on the front there should be a paint mark that covers either 4.8 or 5.3 and that is the way the factory new which was which on the line. It did on mine but it may not actually be correct, I only had one motor to check it on.

Which did the paint cover, the size it is or the size it isn't?

[dwcsr]

Originally Posted by Slow Build

Which did the paint cover, the size it is or the size it isn't?

The size it was.

[Slow Build]

Originally Posted by dwcsr

The size it was.

You may be right. I can't find anything identifying number wise on the motor I'm looking at but I do see some yellow paint over the 4.8. I also found out that the vin# if available will have a V as the 8th character if it's a 4.8 and a T if it's a 5.3 so I found another truck in the same yard that had a bad motor and found a T in the vin# and yellow paint over the 5.3 on the front of that motor.

Originally Posted by '68OrangeSunshine

I know nothing about LS motors,

The engines I'm asking about are the Gen IV V8's.

['68OrangeSunshine]

I know nothing about LS motors, I'm strictly a '67/'72 owner, but 4.8L was the later designation for the L6 292 cu in. 350 = 5.7L. So I'll guess 5.3 is 327 (or thereabouts). So did they make a 4.8L V8?
[I heard Ford in the '50s came out with a 292 V8 ( no relation to the Chevy 292). I have also heard the Ford guys consider a dog. But I'm very fuzzy on Ford lore.]
Here's a bump, at any rate.

[Daaaanz67]

Check out ls1tech there is a good post on this subject
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[low69chevy]

I kno on 99-06 gen III engines they have dished pistons like the 04-06 moreless most of them have the 706 heads and the older ones have the 862 or 863 can't remember behind the bracket where the power steering/alternator go it should be marked or behind on the block where it bolts up to the trans. On the genIV they had flat tops with 799/243 heads and some of the sensor were moved around (knock sensors,cam sensor,map sensor) and the gen 3 had the 24tooth reluctor wheel and gen4 have the 58 tooth.
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[whitels1]

Pull the oil pan and look up the casting number on the crank, the only difference between a 4.8 and a 5.3 is the crank and rods, and the 4.8 has flat topped pistons and the 5.3 has dished unless it's an aluminium 5.3.

[JNJchev77]

If you can't pull the head(s), pull the plug for cylinder one and with a small light, look inside and rotate the engine, manually until you can see the top of the piston. If it's dished (small lip), it a 5.3.... if it's flat it's a 4.8. Only way to tell! Just like whitels1 said...

[vettedad61]

There is a tab on the head gasket between the engine block and head, the tab is behind the exhaust manifold on both side of the engine... The tab on the head gasket is stamped 4.8 or 5.3.