what makes a LS1

[anfking6908]

i currently recieved a 5.3L gmc 323 out of a 2000 Sierra n I was wonderin wat do i have to change out to make it a LS1 motor? what are the big differences?

[Orcus79]

block, bore, heads, crank about that stuff

[SSTODD]

LS1 is aluminum block and heads, truck motors are iron block. That may be an advantage if you are building extreme power as alot of high power bored and stroked motors are iron.

[440 rwhp trans am]

LS1 is aluminum block and heads, truck motors are iron block. That may be an advantage if you are building extreme power as alot of high power bored and stroked motors are iron.

yup go iron if your going big!

[anfking6908]

ok where should i start at? what brands are the best for this setup? this is going to be just an everyday street rod hopin for round 500rwhp.

[1 FMF]

I would start at chevyhiperformance(.com) and gmhightechperformance(.com) magazines. I don't know what you're goals and budget is. If you got a 5.3L free, then it may be worth building that if aftermarket parts are available for it. I don't know the details of the 5.3L and if LS1 parts will fit into it, like crankshaft and heads. If not then you may want to go with a LS1 or LS2 block, where the aftermarket is huge and you can select from anything to everything and build accordingly. All the GM and aftermaket interest is curerently and probably for a while into the LSx motors, both aluminum and iron. That'll also help if you're fitting an LSx motor into something other vehicle, there's quite a bit of aftermarket dedicated to fitting the LSx into anything with wheels. I don't know if you'll have it as good with a 5.3L engine. Check out the "LSX" article at GM hi-tech performance.
... by LSx, I mean LS1/LS6 or LS2, or LS7. LSX is a new block coming out, don't think it's available yet though.

[jag42420]

If you're building for performance, definitely change the camshaft, springs, retainers, and rocker arms. Those motors were made for trucks and the power bands are typically in the lower RPMs. A good camshaft/valve train is the first thing you need.

The bolt ons for a Vortec are similar any other Chevy small block, so the same basic principles apply (bolt ons like exhaust/intake modifications are excellent investments for any performance machine). Don't try to convert a non LS1 into one, just work with what you have.

If you're starting with a cast iron 5.3 (they came cast iron or aluminum), the weight will have to be offset with more torque. Where you go from here depends on whether you plan on a teardown or not and more specifically your budget. Opt for some good aluiminum aftermarket heads if you can afford them. Your stock heads will be hard pressed to get to your 500HP goal. Heads can be changed later if ca$h flow is tight, but would be much easier to change before dropping the motor in. New aluminum performance heads can also be ordered with higher lift springs, retainers, etc...

Here's a little 5.3 info:

5300
The Vortec 5300, or LM7/LM4/L59, is a V8 truck engine. It is a stroked (by 9 mm) version of the Vortec 4800 and replaced the 5700 L31 in 2003. L59 denotes a flexible fuel version, while the LM7 is a special low-emissions engine. The L33 is made for the pickup trucks.

All Vortec 5300s are based on the new Generation III small-block V8. Unlike the all-aluminum LM4 and L59, the LM7 uses a cast iron block. The block and heads are the same as on the 4800 LR4. Power output is 285-295 hp (213-220 kW) and torque is 325-335 ft·lbf (441-447 N·m). Displacement is 5.3 L (5328 cc) from 96.01 mm bore and 92.00 mm stroke. Vortec 5300s are built in St. Catharines, Ontario, Romulus, Michigan, and Silao, Mexico. The L33 is an all aluminum block, with higher compression. This application has 310 hp and 335 ft·lbf of torque.

LM7 (iron block, low-emmissions) applications:

Cadillac Escalade
Chevrolet Avalanche
Chevrolet Express/GMC Savana
Chevrolet Silverado 1500-2500/GMC Sierra 1500-2500
Chevrolet Suburban/GMC Yukon XL
Chevrolet Tahoe/GMC Yukon
LM4 (all-aluminum) applications:

Chevrolet TrailBlazer EXT
GMC Envoy XL
2004 Chevrolet SSR
L33 applications:

Chevrolet Silverado 1500-2500/GMC Sierra 1500-2500

L59 (flexible-fuel, allowing E85) applications:

Chevrolet Suburban/GMC Yukon XL
Chevrolet Tahoe/GMC Yukon
2007 Chevrolet Avalanche
2007 GMC Sierra Classic