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5.3L Build Advice

Bryan Spear
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Bryan Spear Enthusiast

Bryan Spear

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Hello,
I just received a used Chevy 5.3L Vortec engine (LM7) out of a 2003 Silverado. Everything on it is stock at the moment and I would like to build it so that it can produce more than the stock 300 HP and keep it naturally aspirated if possible. I was already considering changing the cam, intake , and throttle body but would like to know what others have done with these engines and what's recommended. Thank you.

asilverblazer Senior Enthusiast

asilverblazer

Posted
Posted

If I'm doing a cam swap, I'm going to hit all the valvetrain with upgrades.

 

Intake and throttle body aren't going to be big power sources. However those are pretty easy to do - as part of a full bolt-on process, tune, headers, CAI, intake manifold and throttle body, exhaust, maybe some bigger injectors, colder t-stat for more aggressive tuning.

 

That should be a pretty potent engine without pulling heads.

swathdiver Senior Enthusiast

swathdiver

Posted
Posted
3 hours ago, Bryan Spear said:

Hello,
I just received a used Chevy 5.3L Vortec engine (LM7) out of a 2003 Silverado. Everything on it is stock at the moment and I would like to build it so that it can produce more than the stock 300 HP and keep it naturally aspirated if possible. I was already considering changing the cam, intake , and throttle body but would like to know what others have done with these engines and what's recommended. Thank you.

 

As the old saying goes, how much do you got to spend and how fast do you want to go?  As ASilverBlazer said, there's a bunch of stuff mentioned that contributes little or nothing to performance.

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

Do a camshaft and headers with a tune. Add an intake if you want. I'd probably go with slightly larger injectors just to be safe.

 

Keep the stock throttle body and intake manifold. Should be an easy 35-40hp with cam and headers.

 

Stock thermostat is just fine, no reason to run a colder one.

  • 3 weeks later...
swathdiver Senior Enthusiast

swathdiver

Posted
Posted
On 1/13/2022 at 10:10 PM, CamGTP said:

What's your budget?

 

Zero or was he too impatient to answer questions for a thoughtful answer?

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

I haven't checked prices in a long time but Speed Engineering headers are still rather cheap and the next step up are Texas Speed headers. Past that you are talking $1,000+ for some headers more than likely.

Bryan Spear Enthusiast

Bryan Spear

Posted
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Posted
16 hours ago, CamGTP said:

I haven't checked prices in a long time but Speed Engineering headers are still rather cheap and the next step up are Texas Speed headers. Past that you are talking $1,000+ for some headers more than likely.

 

Any idea if those vendors will clear Novak engine mounts in a Jeep Wrangler TJ frame?  Thanks.

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

No idea. They are made for truck frames. Anything else is a complete toss up.

 

You'd have to contact someone who has done a swap before to see if it's possible.

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