speedtigger

iTrader: (16)

If you do that, you will likely have to have it balanced at a machine shop as I would bet that the 5.3 rods and pistons have different rotating weights than the 4.8 stuff.

lsthirdgen

I will research it first but I don't think so. the pistons are the same and the crank and rods will be a matched set so I think it'll be ok. thanks for the heads up though, I'll look into it for sure

ZONES89RS

iTrader: (25)

You should be able to select the bottom link for sharing, then it will post the pic here.

NemeSS

iTrader: (127)

5.3= 3.78 bore. 3.622stroke. 6.098 c.rod
4.8= 3.78 bore. 3.268stroke. 6.276 c.rod
The balace will be different as the piston is different type dish vs. Flat.
And the rods have a significant difference in size. The 4.8 rods are heavier.
Compression height is the same for both.pistons. Take it to a machine shop or get it assembled by an engine builder.
The heads are sufficient, you will hurt performance more by hogging them out. If anything just leave the 706 alone and find a set of 243/799.
Mill them some and pay for a matched custom grind. This will more than likely net the best results.
Trying to make an iron ls1 is a waste.of time imo. Ive been there.
It will require -.120 minimum of metal to be removed from the cylinders. Bore and then hone. And balance of crank for new ls1 size rotating assembly.
You are ci ahead by finding a 6.0. And less hassle. Apply your cash to a 6.0 based build.
Or just run the 4.8 as is, til gather funds for bigger motor.

lsthirdgen

I thought the 07 and up 5.3 pistons were the same flat top design? if so I would think if I got a crank and rods out of a 5.3 all should match up fine since the crank and rods are a matched set with the same piston. Unless I'm missing something?

BLK95-Z

iTrader: (2)

Im interested in how ths turns out. I have a good 4.8 in the garage Ive thought of building like this.

ZONES89RS

iTrader: (25)

I will be doing cam only in my 91 RS, but the spare 4.8 for the future s10 will be ported ls1 castings and spin 7800 or so. I think a 4.8 will be fun, just need to spin them. Just get a 5.3 if you just deem needing the cubes just because it would be money saving to just run the engine that started as a 5.3.

lsthirdgen

Idk if I "need" the cubes but they would be nice. But like I said I'm only going that route if I come across the parts cheap. As you can see I'm kind of indecisive lol.I am however leaning toward going 4.8 just for simplicity as long as I can get what I want out of it. Thanks for all the help everyone!

lsthirdgen

lsthirdgen

HA! it worked. thanks!

ZONES89RS

iTrader: (25)

There ya go, nice ride btw. Got any more pics? Looks way better than the RS I just got.

NemeSS

iTrader: (127)

Im a big fan of 4.8s.
My dd 4.8 has 349k miles. On stock longblock. They are very reliable engines and can take alot of abuse. If maintained.
As a matter of fact.
I have 09 4.8 with studs,ls9 gaskets,317 heads on a stand waiting.
I plan on running 20psi thru it on pump gas with a turbo.
Just looking for 3rd gen to drop it into.

lsthirdgen

lsthirdgen

lsthirdgen

hmmm not sure why the one is small but here ya go. do you have pics of the rs up anywhere?

ZONES89RS

iTrader: (25)

The new one is in the new post, i think you may have seen by now, i have not checked that post yet.

ZONES89RS

iTrader: (25)

Nice BTW, what wheels you have planned in the future?

lsthirdgen

im not really sure. ill probly just keep an eye out for something i can pick up cheap. id like a set of 18s. whatever i find will get painted black for sure though,just not rattle can this time.lol

BLK95-Z

iTrader: (2)

I like the yellow with black wheels look. I think some 18" gunmetal z06 wheels would look sick with a little lower stance.

lsthirdgen

i love the look of z06 wheels on these cars but im just not willing to run 2 inch wheel spacers