SCLT1

Pulled a motor out of a 2004 Chevy Silverado 1500. Figures for sure it was a 5.3L. Now I’m worried I got a 4.8L . Originally didn’t want to get away from the 5.7 original LT1 I had but read a lot about the 5.3 and liked the idea of boosting it. The block says both which I read is normal. It’s a iron block. Aluminum heads had 4.8L stamped inside of one of the valleys and they are flat top pistons with a cross sign stamped on them.. Haven’t pulled the oil pan yet as still cleaning things up on heads. Really bummed out and hoping the head stamp doesn’t mean anything... oh and 862 heads if anyone was wondering. Also I did search and found mixed results so wanted to post on here. Thanks!

DavidBoren

Given that you already mentioned boost, what does it matter if you have a 4.8L vs a 5.3L?

From a performance standpoint, they are similar enough that it's not worth getting bummed about.

I know you said you didn't want to stray too far from the 5.7L LT1, but displacement is just a number... a stock 4.8L performs just as well as a stock 5.7L LT1... 300hp is 300hp.

SCLT1

Well they sound different for one reason. LT1 with some stuff done to it sounds mean as my old setup did.. 5.3 sounds pretty good too but the 4.8L I have heard that guys put exhaust on for the trucks just don’t sound as mean. The displacement thing makes a difference, sure I can build around it but just wanted a 5.3. Mechanic friend I talked to said it happens pretty often unless you have the time in the junkyard to look at the crank stamping.

G Atsma

The ONLY difference between 4.8 and 5.3 is the rotating assembly. Actually just the crank and rods. Pistons are interchangeable, but 4.8 got flat tops and 5.3 got 8cc dish.

SCLT1

I read some years 5.3 had flat tops... Would it be crazy to bother getting a stock 5.3 rotating assembly and swapping out from a junkyard or wherever? I know someone that has one but pistons have damage from valves hitting them.

Michael Yount

iTrader: (1)

Sounds like you want a 5.3 --- sell the 4.8 and buy a 5.3. What am I missing?

SCLT1

Wish it was that easy but with paying $300.00 for this one and a two hr drive to remove it that’s not a option. Plus no one to sell this one too around here.

G Atsma

Gen IV 5.3's have flat tops, but also larger chambered 243/799 heads.
All Gen III 5.3's with 706/862 heads have dish pistons.

gofastwclass

iTrader: (2)

The VIN of the vehicle the engine came from will tell you displacement. If you're going turbo who gives a turkey. If you are so concerned about a few cubes or it won't sound "mean" enough (whatever that is) I agree with Michael, sell it and move on.

I understand there is no replacement for displacement but that only applies if you're trying to make maximum power as in racing. Honestly no one will know unless you tell them and the remaining people won't understand the difference or care. I would also bet a nickel in a double blind test you won't be able to tell the difference 10 for 10 on your butt dyno in the same chassis.

SCLT1

I know you guys are right but have it stuck in my mind . Like I asked would it be worth the hassle to switch out to a 5.3 rotating assembly? Truck is 2hrs away so can’t go check it. But think it was a two door and not a crew cab...

Michael Yount

iTrader: (1)

"....would it be worth the hassle...." --- "I.....have it stuck in my mind." What is it you want us to help you with? If you absolutely want a 5.3 (have it stuck in my mind) - then make it a 5.3L. You don't need our help with that.

Where are you gonna get the rotating assembly?

SCLT1

Guy I know has whole rotating assembly I would just need new pistons as ones he pulled from a guys motor are damaged.

Michael Yount

iTrader: (1)

Great! Quit futzing around on here -- show us pictures after you get the assembly swapped. You know what you want - go do it.

SCLT1

Thanks man. To many times with hobbies I settled with something I didn’t really like or want and wished I didn’t..

1FastBrick

iTrader: (16)

Except the L33 which also had flattops and 799/243 heads...

G Atsma

Which is why I mentioned the 706/862 heads. My main point was that the most common setup was those heads and 8cc dish pistons.
The L33 was the lone exception, and became the rule for Gen IV 5.3's

RedXray

A cammed 4.8 sounds meaner cam lope wise than a 5.3 with the same camshaft. The smaller displacement engine will sound off, put that same cam in a 6.0 it will sound almost stock. Like everyone posted... If you're going turbo stop sweating the little displacement numbers between the two and send it.

SCLT1

Putting a blower on it and a guy has 5.3 stuff what I need except one bad piston but can’t make up his mind what he wants to do with the assembly haha.

SCLT1

Mod please close this thread! Thank you.

Michael Yount

iTrader: (1)

This is like an SNL sketch....good luck!