AlexTVR

I know you can punch out the 5.3 to 5.7 bore,

But are the gains really worth the time, money and effort?

By the time you got bought new pistons, stripped the block, bored it, honed it, full balance and gasket set is alot of effort

Has any on here done this and thought I wish I never bothered and spent the money else where


Alex

2000PewterT/A

In my opinion just buy a 6.0 and save the hassle.

RezinTexas

I did it and I'm happy with my choice, however going to a LQ4 block will likely be around the same price once you pay the machining costs on the 5.3 block.

kossuth

iTrader: (12)

Depends.... How cheap did you get the 5.3 block for? What are your machining costs likely to be in your area? What can a 6.0 block be had for locally around you? That's the real question.

Suprfast

If I had a 5.3 I would stroke it to 383. Also the 6.0 is a better choice for the money

AlexTVR

I didn't get the 5.3 cheap compared to you guys, and its all built up

6.0 blocks are nearly impossible to come by here in the UK so not really a option.

Its a L33 and I need a all aluminum block for the weight saving, the car weighs 2300lbs as stock and adding the extra weight would really mess up the handling of the car.

Only reason im asking is because I'm considering some forged pistons because I want to spray it, and the ole 'while you're there' I might as well put some 5.7 pistons in.

I was planning on a large cam,rod bolts, valve job and 200-300shot

Should I just spray it and if it does blow add the 5.7 forged pistons then?

kossuth

iTrader: (12)

Here's the deal. If you blow it, it may or may not be rebuildable regardless of the bore.

96capricemgr

iTrader: (1)

Blowing up a motor might be as little damage as a broken piston or it is possible to have little but the intake manifold left salvageable. If core blocks are hard to come by there then you mi9ght not want to risk it.

Far as the overbore I haven't really looked into it, can you bore the ALUMINUM 5.3L to 5.7 spec? I know it can be done on the iron block just not sure about the aluminum.

More displacement more than anything allows for larger heads and cam within a given rpm range, the overbore can help the heads breath a little better too, but the ability to run a "bigger heads and cam" is the biggest advantage.

Are you planning on stock heads with just a valvejob? Heads are more important to HP than displacement, 100% of the air in and out has to go through the heads as controlled by the cam. With the size shot you want forged pistons are a really good idea but at the same time it would IMO be a mistake to focus so heavily on the bottomend and then not even port the heads.
Which heads are you using?

AlexTVR

I got the 799 heads, I was planning on a valve job and just a tidy up, as postage, import duty and tax would make having my heads sent off quite expensive.

I'm looking at the new polluter V2 cam or MS3, Looks like a nice big cam to suit a lightweight car, I want to move as much torque as possible up the rpm range, it has a tendency to spin the wheels every where even with my old rover v8 engine

I've read up on people putting 250 shot in a stock bottom end with no issues,

By the sound of things gaining the extra's 400cc's would be good, but money would be better spent else where

96capricemgr

iTrader: (1)

I would put money into making it rpm reliable more than hunting displacement. The displacement is just going to make lowend stronger and well seeing as the 5.3l is the most common engine in the trucks that are very often well over double the weight of your car I think it will have enough torque to keep your hands full.

Over here extended cab and crewcab half ton trucks are HUGELY popular and a crewcab 4wd truck has a base curb weight of I believe around 5300lbs for my 2005 model, that is a full 3000 more than what you are looking at and the torque is adequate with the tall 32inch ish tires and 3.42 gears.

AlexTVR

I think your'e right,

Where money best spent to make it rev?
I got a LS2 intake, 92mm TB, 30lb injectors, arp rob bolts so far

V8 trucks are a very rare over here, most are turbo diesel engines

96capricemgr

iTrader: (1)

Recondition the rods with the ARP bolts then spend the money on valvetrain

garygnu

a 92mm fast intake will net you 10 hp.consider a EPS cam.check Texas Speed for parts and shipping .

AlexTVR

Thanks for the great info guys,

Regarding the balance of the engine, were they balanced well from the factory or is it worth having it all re-balanced and checked?

So im looking at arp bolts, titanium spring retainers, double springs, a cam 23x-24x duration, roller rockers worth the cash?

Is 7500-8000rpm possible?

Thanks

kossuth

iTrader: (12)

Well balanced??? They are factory pieces so its balanced well enough for 2000 rpm daily driving. You need to fully balance the entire assembly.

As for 7500-8000 rpm, yeah its possible but doing this with a motor built for longevity isn't going to give you much oops room if you get a weak spring or some other weakness. IMHO I would be looking to keep it down around 6500 or so and your valve train will be much more happy.