rynestone

Im having a hard time finding out what motor I actually have. I bought what I thought was a 5.3 out of a 2002 pick up but I didnt get the vin. I cant read the tabs on the head gaskets and I really dont want to drop the oil pan, can anyone lead me in a direction to finding out what motor I really have? and if its a 4.8 what kind of loss is it compaired to the 5.3? can it be made up for in a tune, as its going in a jeep cj. Thanks

bww3588

iTrader: (49)

Easiest way to tell is to look at the pistons If the heads are off. 4.8 will have flat tops. 5.3 will have dished pistons. Otherwise, stick a straw down the cylinder and turn the motor over by hand. 5.3 will have a 3.622 stroke, 4.8 a little bit shorter. Not sure exactly. I also believe the 4.8 had cast iron heads until 07. Don't quote me on that tho.

SSjon

iTrader: (4)

The 6.0L is the only LS engine that ever came with cast iron heads.

99VetteFRC

My 4.8L has aluminum heads and it has "4.8l" cast in the back of the block on the right side. Mine is a 2003.

Strokinit383

iTrader: (22)

This is the only way to tell the difference.^^^

91sonomast

Or you could do this.......it's possible someone put a 5.3 crank in the 4.8 but doubtful.

Strokinit383

iTrader: (22)

I've only seen them marked "4.8/5.3"

bmech211

OK, now I'm confused. I have what was advertised as an LY5 5.3 short block and the pistons look like these L33 pistons, which are flat tops.


Guess I need to put a cylinder bank back together and measure.

bww3588

iTrader: (49)

Check the rod length. 5.3 will be about 6.1. Any machine shop should be able to quickly tell you the rod length. Doubt they will charge you if they aren't busy

camarozz383

iTrader: (3)

my 2008 lmg 5.3 has flat tops!

i r teh noobz

iTrader: (4)

A 2002 5.3 will have dished pistons.