Chicago TDP

iTrader: (3)

I have a 4.8L stock short block with a TC76...just hit 16 PSI of boost....still tunning with HP Tuners at the moment to get the tune right....160# injectors....going for 700 HP

JRENIGAR

iTrader: (37)

hah, damn...

COOKIE MONSTER

iTrader: (5)

That's a hell of a build

Johnmaster

iTrader: (3)

The 5.3 I am working on has almost 220,000 on it right now, getting ready to finally boost it soon. I may be trying to prove a point but I really don't see taking it apart unless there was something wrong with it. Even then it would just be for an autopsy, I can get another good used one for slightly more than changing head gaskets would cost. The long block to me is entirely disposable, I can spend more for the turbo carb hat than I would for an entire good running long block with a salvage yard warranty! Just goes to show how well they built them by how many are available for so cheap.

Loudmouth LS1

iTrader: (10)

Looks like i'll be joining you guys for a little while. Picking up an 80,000 mile 5.3 shortblock this weekend to throw in and build everything around. It will be getting a GT88 turbo on it and obviously i'll keep the boost down until I build a motor, but i'm going to push for 9's out of the stocker and i'll be on e-85, so that should help a little. I'm hoping it holds up for a little while so I can have some fun while I build a motor for that turbo.

Zerex

So whats keeping these stock bottom end 5.3's together? Is it keeping the rpm low or just a nice fat tune? Everyone used to swear you had to change rod bolts, and now everyones sticking with complete stock shortblocks.
Discuss

JRENIGAR

iTrader: (37)

Im also curious. I have been pondering if the stock ls1 pistons being out of the bore a lil bit is causing cracked ring lands. I dont know if the 6.0 or 5.3 has this issue or not? What are the diff in rods n bolts, what material are the pistons made of? Maybe a vendor can contribute to some info???

5.3-on-steroids

iTrader: (3)

Check out the september 2011 edition of hotrod magazine coming out. They did another junkyard 5.3 turbo dyno run but this time they were just trying to blow it up to see what the upper limits really were because so many people had different opinions on how much they could take. All they did to the motor was drop on a set of ported stock castings and open the ring gaps to .035 and a fast 102 intake made a chicken **** twin turbo setup with a set of shortys and chinese turbos and they pushed it all the way to 1,250 hp at 27.8 psi with no problems at all and it wasnt only 1 or 2 pulls making 1,250 they did over 60 pulls on the dyno at that boost without any problems so it wasn't luck. They had great tuning and all the pulls were done on vp 118 fuel and they never could blow up the engine and a few of the coils took a **** before the bottom end did and the ironic part at the end is when it dawned on them that the motor was actually a 4.8 and not a 5.3 at all lmao check it out it was a good read.

JRENIGAR

iTrader: (37)

So how do you tell if its really a 5.3 or a 4.8, supposing you bought it off a junk yard or ebay???

5.3-on-steroids

iTrader: (3)

5.3 will have the 706 or 862 head castings and dished pistons

JRENIGAR

iTrader: (37)

So what heads does the 4.8 have? I wouldnt want to pull the heads and check pistons as the junkyard probably wont allow that. Im wanting a sure fire way to tell from the outside what size engine it is.

Project GatTagO

iTrader: (7)

The displacement is cast right onto the back of the block.

Andrew

098z28

iTrader: (12)

yeah but a 4.8 or 5.3 says "4.8/5.3" cast into the block....

Project GatTagO

iTrader: (7)

That certainly makes it harder...LOL

My only experience with a 5.3L has been an aluminum block one, which has 5.3 cast on the block.

Andrew

JRENIGAR

iTrader: (37)

This was my understanding as well, although I have never verified it myself. HMMMM.....

JRENIGAR

iTrader: (37)

Do you know what years had the aluminum block or if they are physically any different as far as changeover goes than the iron ones?

LSJM1

iTrader: (15)

Can't you shine a flashlight in a spark plug hole with a piston towards the top and tell if it has flat top pistons or not

JRENIGAR

iTrader: (37)

I thought the only diff between the 4.8 and 5.3 was the crank stroke.

Johnmaster

iTrader: (3)

I am sure you could use the serial numbers to figure it out but otherwise the bore is the same, stroke is 92mm on the 5.3 and 83mm on the 4.8. Doubt you could get an accurate measuring device in there.

JRENIGAR

iTrader: (37)

True enough, I was thinking the pistons probably look the same too. If there are subtable differences it might be hard to see through the plug hole, especially if they are covered in carbon deposits. We need answers people.