Cam Query


Well-Known Member
I am not an engine guy. I know of a lot of things that can be done under the hood and I can swap out basic items, but when it comes to the nuances and inner workings, I lack a full understanding.

For instance, I know that changing the camshaft, something I wouldn't attempt myself, is how some guys get that aggressive, loping sound from their engines. And after a little reading I know that a camshaft upgrade can go the other way too, making for an even smoother running sound at the cost of HP. It is also my understanding that you don't swap the camshaft until you have done any other mods you have in mind (intake, exhaust) because the type of camshaft you go with will depend on those factors. Beyond that, it is a lot of technical engine jargin that leaves me at a loss.

For what I have in mind, I would like to eventually give my Tahoe a slightly more aggressive sound, but not the full loping some guys go for. I want it to be just noticeable so that another car person would recognize that something is different, but others might not notice Some say that you can get a .5-2 mpg gain from intake or exhaust upgrades and I would like to think that the cam upgrade would negate this. What I would like input on is: Is it even worth it? Would I be able to get that 'just noticeable' sound before taking a big hit in mpg?



Silver Supporter
Is the only thing you're looking for sound and possible mpg improvement?
Is your engine in a condition or high mileage that it may need to be overhauled?
Are you planning to do the engine work yourself or are you planning on having a shop overhaul it for you?
Have you had a tune done to your engine/PCM?

If your engine mileage is below 200k miles and you only want the improved exhaust sound and possibility of mpg improvement, I would say it's not really worth it.

If you want the sound, you could delete (remove) the resonator and muffler to get the sound you're looking for. Just replace the muffler with an improved/enhanced muffler, meant to enhance the exhaust sound, like Flowmaster.


Well-Known Member
I agree with @Maverick6587 on this one. A good tune (see @limequat or PCMOFNC), and a good muffler, I think you would gain all the performance and sound you are looking for, at a much more cost effective pricing.


Lifetime VIP Supporter
Gonna have to agree with the others here. Sound & (potential) mpg improvement? Get a performance exhaust (a muffler, up to a full dual catback). You'll be happy & money / time ahead to boot. You'll also feel a small HP gain via the 'butt dyno', with the less-restrictive exhaust.

I went the other way (Flowmaster to conventional muffler) recently, and I could tell there was a small reduction in throttle response afterward (which I was fine with, to give up the drone of the Flowmaster). The vehicle I have it in is a dedicated tow vehicle, so it won't be daily driven - but, when it is, will be driven for a few hours on end, at mostly interstate speeds. Then there's the whole 'don't wake up the campground neighbors' thing, when in a campsite and needing to get an early start for the next day's travels.

If you really want the physical lope... only a cam will do that (unless maybe you pull a couple of plug j/k). But it can be a bit much to deal with as a daily driver. From what you're describing, I'm guessing you'd like the 'lope' sound, without really losing the idle quality. That's kind of hard (if not impossible). Would likely require a 'stage 3' or '4' cam, and definitely a tune, to make the most of its capability. Forget about fuel economy, as well. Finally, when you start getting into changing idle quality, the torque / HP characteristics tend to change. As someone from Comp Cams advised me, a really lopey idle is also one that is suited for high-RPM hp and torque, sacrificing it on the lower end, but gaining it higher up.

To get the physical lope, you're looking at a cam, definitely upgraded valvesprings, and new lifters / pushrods would be advisable, too, especially if you select a cam with a lot of lift over stock. That means the heads are coming off. Since you're in the front cover for a cam, a freshening of the timing chain would be a no-brainer, if your engine has a lot of miles on it.

I'm about to start my own tow cam upgrade, along with a build thread. However, it's not going to be a "do it in a day" (or even weekend) build. This is going in a Sierra with a 6.0L LQ4; a little bigger than your 5.3, but the same basic 'LS' principles will apply, if you want to follow along and decide if it's something you want to get into. Also, there's @MRRSM 's build thread; he did a cam swap in his 4.8 Silvy recently, and he posted a LOT of updates on what he did, issues he ran into / resolved, etc.


Well-Known Member
I definitely would not do something like this on my own. Replace a starter or alternator? Sure. Getting i to the innards of the engine where all sorts of things need to be adjusted (like mentioned about springs, etc), I just wouldn't touch it and take it to a shop to get it done.

I am already planning an intake upgrade and a flowmaster Super 40 for a good growl without getting 'too loud'. But there is a difference between a louder exhaust and a loud exhaust with that wump wump wump sound in it. I wasn't thinking of improving mpg with the cams so much as the cams would negate whatever gain I got from the intake/exhaust.

The Tahoe, an 05, has 170k+ miles on it and I am planning to take it in for an overhaul since I don't know how well the previous owners took care of it. And while it is my daily driver, I want to get it show-worthy and am figuring out what I want to do to set it apart and a mild cam upgrade came to mind. But as my daily driver, reliability is an issue. I don't want to be like a friend of mine who suped ip his CTS-V only to chase problem after problem every month.


Silver Supporter
Well then! If you're going for show worthy and reliability! I would switch to gen 4 LS internal block components then (rods, pistons, rings, crank, possibly cam [since you want to upgrade])

A second option beyond the internals would be switching from the aluminum block to the iron block.

The gen 4 LS block internals can take 1,000+ HP and will basically last "forever". I have an 07 9-7x 5.3 with 230k miles on it and I give it the gas every day without concern.

Make sure you switch to the 56x reluctor wheel and get a tune (you'll need to have the ECM know it has the new 56x reluctor anyway) so, at the 56x reluctor learn to the tune.

I'm sure more members will have other opinions and/or differing opinions but, that's what this site is for, all the opinions and knowledge.

Here's a guy I've been following that explains the gen 4 vs gen 3 LS differences.


Well-Known Member
Just so I am clear, are you saying swap out internals for LS Gen 4 internals or swapping out the block itself for a LS Gen 4? Obviously you mean block when you say swap from aluminum to iron, but an engine swap just isn't in the cards right now. Maybe if I ever the extra money to build an engine on the side, but for now that would be too much downtime.

Thanks to everyone thus far.


Silver Supporter
Good point, guess I wasn't clearly thinking that though through. Honestly it would cost you a few hundred more depending on the prices at your local junkyard but, I would go grab a 2007+ (Gen 4) 6.0 L from a Chevy Express, Silverado, or Cadillac Escalade. Have that engine rebuilt and then swap your 5.3 for the 6.0.

If the upgrade scares you at all. You could do the same thing with a 5.3 2007+ (Gen 4). In either case, when you swap them you could sell your 5.3 as a running engine for over $600. At the you pull it yards around me the engines are $200-$300 depending on the yard. I've actually already done this once to know it works. Snagged a 5.3 from a junkyard, didn't even know if it ran and sold it, stating that I did not know it's condition, for $600.

It's too cold to be doing that right now but, that will be a nice little Spring project for me.


Well-Known Member
It's beautiful weather for me, Florida, but that isn't in my near future. We are currently house shopping and are looking for a garage that I can tinker in, but right now all work would be in the elements and the majority of funds is being set aside for the house. I would actually love to do a 'dry build' from the block up and take it to the pros to have everything adjusted, calibrated and tuned, but it just isn't reality for me.

And maybe the camshaft is in the same ballpark, but I was 'thinking' when I got the overhaul they could do the cam swap and retune at the same time, but I was wrong in that thinking I guess.

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