GM 4.8L V8

I'm so pissed off....I just built a damn tbi 350 with vortec heads for my suburban.....should have gone LS.....argggg. Maybe I'll try and sell the 350 on cl and come over to the LS darkside.

I saw on another forum while browsing for 4.8L stuff, that a guy went to a local auto recycler and they had several 4.8s, 5.3s, and 6.0s, when he asked prices they told him $300 for the 4.8 and $600-$700 for the other two. He asked why and they said the 4.8 is not a desireable motor.

I feel otherwise

I love the idea of a high revving V8, regardless of how impractical.

Is there REALLY that big a difference in the reliable rev ceiling between the 4.8 and 5.3 or even the 6.0?

My dad used to have a 283 in a 38 Chev coupe and he used to turn it to 7500.

The 4.8 would be similar displacement - The 5.3 is almost identical to the old 327 and some purists will swear that the 327 was the best SBC ever made.

z31maniac wrote: I love the idea of a high revving V8, regardless of how impractical. Is there REALLY that big a difference in the reliable rev ceiling between the 4.8 and 5.3 or even the 6.0?

6.0 guts are heavier . . . I wish I can find that link where they dissected each motor and spoke about the details . . .

There are a few 7500 rpm 5.3 tearing up the strip across the union . . .

I'll leave this right here. . .

Here are the details on this 4.8L

^Yeah, I'm really leaning toward the 5.3 backed up by a T5 to drop in an E30.

But I'm talking about for HPDE use, so it would see those rev's a lot, vs being at the strip.

Build it like another high revving LS motor . . .

• Good timing chain set
• LS6 Oil pump (ported if you choose)
• Good valve springs. . .

Check out the guys over on http://www.v8roadsters.net. They have some 5.3 (of the L33 variety) builds over there. . .

I have a 99 GMC Sierra Ext Cab 4x4 with the 4.8. Has 225,000 miles and still runs strong.

The 4.8's are overlooked motors and left for cheap picking. Belief is "its smaller than the old 305 so it must be a dog" which is incorrect. Die hard 350 people thought the 5.3 was going to be a waste when it came out also.

I would like to buy a S10 and drop one in. Or perhaps a Chevy Monza, since I'd hate to drop my future desire to put a 327 -Tunnel Ram - dual 4's - in an old S10.

There are cheap third gen camaros and firebirds out there also that 4.8 would be nice swap.

The LS motors are also easy to spray.

SyntheticBlinkerFluid wrote: In reply to 81cpcamaro: The 4L80E was an optional trans for the 4.8L and 5.3L in the 2500 series trucks and vans. My workvan has it. The RPO of my van: LR4 ENGINE GAS, 8 CYL, 4.8L, MFI 4.8V(LR4) 9,600 MT1 TRANSMISSION,AUTO,4-SPD,THM-R2(4L80-E) 4-SPD A/TRANS(MT1)

Yep, I should have clarified that the 4L60E was in 1500 series, my bad.

My 2k Silverado has 4.8, 5 speed, 20 mpg Canadian empty at 120k, 16 mpg towing flatdeck with Neon. No great screamer as far as torque goes, but it pulls hard above 3000 rpm.

Trans would not be a suitable race car piece.

Streetwiseguy wrote: My 2k Silverado has 4.8, 5 speed, 20 mpg Canadian empty at 120k, 16 mpg towing flatdeck with Neon. No great screamer as far as torque goes, but it pulls hard above 3000 rpm. Trans would not be a suitable race car piece.

What trans is that? We're talking manual right?

Strike_Zero wrote: I'll leave this right here. . .

WOW!!!

Strike_Zero wrote: Build it like another high revving LS motor . . . - Good timing chain set - LS6 Oil pump (ported if you choose) - Good valve springs. . . Check out the guys over on http://www.v8roadsters.net. They have some 5.3 (of the L33 variety) builds over there. . .

I've got one of their motors in the Targa Miata (V8Roadsters and V8R Spec are both sponsors). It's FUN. I'm using a 6500 rpm shift point and a 7000 rpm rev limiter. Not as monstrous at low rpm as an LS3, but nice and linear.

GM sprinkled some good dust on the LS3. I thought the LS2 was potent . . .

How does it feel with that almost stockish lobe separation angle? Any number yet?

SyntheticBlinkerFluid wrote:

Streetwiseguy wrote: My 2k Silverado has 4.8, 5 speed, 20 mpg Canadian empty at 120k, 16 mpg towing flatdeck with Neon. No great screamer as far as torque goes, but it pulls hard above 3000 rpm. Trans would not be a suitable race car piece.

What trans is that? We're talking manual right?

Its some sort of trucky 5 speed. Not a bull low type, but still with big heavy gears and sticky synchros.

It looks like the LY2 is the 300 hp variant. How hard is it to hop up a LR4 to the LY2 specs.

dean1484 wrote: It looks like the LY2 is the 300 hp variant. How hard is it to hop up a LR4 to the LY2 specs.

AFAIK it's a matter of the ECM. The engines are the same.

The 2011 variant of the 4.8L engine is making: 302hp @ 5600
305ftlb @ 4600

That is getting close to what the LS1 makes in my 98' FBody. Redline on the cluster is 6000rpm.
305hp @ 5,200
335ftlb @ 4,000

z31maniac wrote: I love the idea of a high revving V8, regardless of how impractical. Is there REALLY that big a difference in the reliable rev ceiling between the 4.8 and 5.3 or even the 6.0?

I'm with this guy, I love torque but revving an engine to the moon is even more exciting.

I imagine with headers and an ECM flash, those numbers could go up to LS1 specs easily.

I'd never thought of one before but after hearing all this dirty talk and seeing the porn I wants one.... and a new project to drop it in.

Vigo wrote:

Jesus H., where do you live? Is it rusty (it doesn't look like it, and my current one is). I could totally bring that up from the states...

Seeing 5psi = that level of HP, is making me think about the Texas Mile and similar events.

SyntheticBlinkerFluid wrote:

dean1484 wrote: It looks like the LY2 is the 300 hp variant. How hard is it to hop up a LR4 to the LY2 specs.

AFAIK it's a matter of the ECM. The engines are the same.

The cylinder heads are different as well. The LM4, LM7 LR4, L59 motors came with the 706 and 862 castings (200/70) at 61cc for 9.5:1 CR.

The new motors LY2, L33, LH6, LS2, LS4 motors come with 243 and 799 (LS6 style) castings (210/75 and bigger intake valve).

GM said: The LH6 takes its cylinder heads from the LS6 V-8 that powers Cadillac’s high-performance CTS-V sedan. Originally developed for the Corvette Z06, these heads improve airflow in and out of the engine. With their pent-roof combustions chambers and new flat-top pistons (the pistons in Gen III Vortec 5300s have a slight sump in the piston deck), the Gen IV Vortec 5300’s compression ratio increases from 9.5:1 to 9.9:1. This increase improves the engine’s volumetric efficiency and increases horsepower.

LSx Stuffs . . .READ ME NOW!!

In reply to Strike_Zero:

That link has been added to favorites. Thanks.

In reply to Strike_Zero:

Ahh good to know. Then the LY2 is the way to go.