sman

iTrader: (4)

I just picked up what I believed was a 5.3 for a swap im doing, but I notice on the block it say 4.8L/5.3L. It has 862 heads and that's all I know so far, how can I tell if I indeed have a 5.3 or I need to bash someones head in for selling me the wrong motor?

68 RS Convertible

iTrader: (1)

Unless you know the vehicle the motor came out of and can verify it that way the only other way i know of is to tear it down. I believe all the internals are the same (crank and rod length), but the 5.3 is a larger bore, but if I'm wrong someone please correct me. I'm not familiar with, to put it better I have no clue as to head casting differences between the 4.8 and 5.3. So before you go head bashing try and verify the vehicle it came out of, maybe there is some paperwork with the donor vehicle to verify its a 5.3. Good Luck.

djwimbo

Pretty much what he said, if you knew what it came out of you would have a clue to what it is.
Both engines are identical aesthetically. The 4.8 has the shorter stroke though, bore should be the same(96.01mm/3.780"). The 5.3L should have the 3.622" stroke.

Example, Std Cab trucks came in 4.8L and Ext Cab had the 5.3. The trucks with a towing pkg should have the 5.3 as well.

5.3LJimmy

iTrader: (10)

You can pull the spark plugs and try to look at the pistons, or pull the heads if you plan on taking them off anyway. The 4.8 has flat tops and the 5.3 has a dished piston. You can also pull the oil pan and see what crank it has. 4.8 has 3.28 stroke and the 5.3 is 3.622.

blackLS1m6

iTrader: (14)

Don't the 4.8s have a different rod length?

NemeSS

iTrader: (127)

correct.
4.8 has longer rods and flattop piston
usually the motor will have a paint mark next to the designated displacement.
on 5.3/4.8

jlrz28

iTrader: (7)

Not exaclty, some Ext cab trucks have the 4.8.

regency

iTrader: (15)

only way to really tell is to look at the top of the pistons.

4.8 = 3.27 stroke, 6.278 rod length, and 3.779 flat top piston
5.3 = 3.622 stroke, 6.098 rod length, and 3.779 dished piston

5_02ls1

iTrader: (20)

I have 2 5.3s sitting here and both of them have a big mark next to the 5.3...


4.8
/
5.3/
it should lookl somthing like that on the drivers front of block

347Convert

I have a 5.3 and it has a plat piston? Hmmmm

What block are we talking because mine is aluminum. I belive it is the newer 330hp option package engine.

djwimbo

Alum block is the L33, it's the newer HO version. I did some research on that one not too long ago, basically, you have a small displacement LS6.

red83

iTrader: (64)

all the motors i have seen have always had a mark beside either 4.8 or the 5.3

sman

iTrader: (4)

Guess I never thought about that. Now that I think about it I remember there being a yellow mark in that area on the block. Crap now I just cant remember where it was. Im at work, it will have to wait till I get home. The suspense is killing me.

sman

iTrader: (4)

Well in case anyone was wondering it is indeed a 5.3. Verified by the bore and the yellow paint parking over the 5.3 on the block. But man, its not dished very much, I expected more. Not complaining or anything just expected it to be more "dished" when I pulled the heads.