Best budget upgrades on a 5.3L rebuild?

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tRidiot

tRidiot

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Excellent information! Thanks for the tips!

If it doesn't make sense to upgrade to some of those parts, I don't want to bother. I'm not worried about power above 5k RPM, I don't know that I ever even GET to 5k RPM. Very very very seldom do I ever "get on it", as I don't need to waste the fuel, and if I want to drive "fun", it's a day for my 370.

I'll go watch some of those videos now. Thanks again!
 
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tRidiot

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Avoid the LS9 cam in a 5.3.
Watch this vid with a comparison of all the stock cams in a 5.3



You will gain power above 5000 rpms but will lose upto 50 lb ft of torque on the bottom end.

Wow, that was really eye-opening. For me and my driving habits, I think losing the lower-end torque would be a big problem, not that I'm towing or anything like that, but when you drive it softly - as anyone with a Tahoe even mildly concerned about fuel economy will be doing! - you're definitely going to notice 30-50 less lb-ft of torque.

Thanks for that video, I'm going to go watch more of his, I really like his style. I'm a science guy professionally, so graphs, curves and overlays really help me make sense of those numbers.
 

Mudsport96

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Wow, that was really eye-opening. For me and my driving habits, I think losing the lower-end torque would be a big problem, not that I'm towing or anything like that, but when you drive it softly - as anyone with a Tahoe even mildly concerned about fuel economy will be doing! - you're definitely going to notice 30-50 less lb-ft of torque.

Thanks for that video, I'm going to go watch more of his, I really like his style. I'm a science guy professionally, so graphs, curves and overlays really help me make sense of those numbers.
Yeah, and like i said the bonus is hes not selling anything. So its all objective tests, he even did a short one on the 243/799 heads vs 706s on a 6.0 Lq4. Many people look for every last hp which is cooland all, but the 706s gained 12tq in the useable area a heavy suv would need it.
 
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tRidiot

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Yeah, and like i said the bonus is hes not selling anything. So its all objective tests, he even did a short one on the 243/799 heads vs 706s on a 6.0 Lq4. Many people look for every last hp which is cooland all, but the 706s gained 12tq in the useable area a heavy suv would need it.

Yup, I just saw that video, too. Pretty good channel there. May save me a lot of money in the longrun, lol. Looks like not a lot of benefit to making a lot of the changes I was considering. Just going back with a basic rebuild for my basic driving sounds like a pretty good option.

Thanks again.
 
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tRidiot

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Yeah, and like i said the bonus is hes not selling anything. So its all objective tests, he even did a short one on the 243/799 heads vs 706s on a 6.0 Lq4. Many people look for every last hp which is cooland all, but the 706s gained 12tq in the useable area a heavy suv would need it.

If I could get some good 706s that were not Castechs, that might be a good option.
 

iamdub

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This sounds good, but I'm not sure where I would get these. We honestly don't have any salvage yards here, would have to drive to Tulsa (about 45 miles) and dig through junk yards. And I don't know that I have the time for that.

Honestly there aren't many sets on Ebay (for an L59) that aren't 706/862, and several of the ones I can see obviously have the Castech mark in the pics, which is a no-no for me, and others I can't see if they do or not. I haven't had good luck with Ebay sellers when I've asked questions about this topic, mostly not getting replies - and surprisingly, even one highly-recommended engine remanufacturer I contacted in Tulsa acted like they'd never heard of a problem with the 706 heads. That freaked me out even more, as this seems such a common issue and well-known, I can't imagine someone who remanufactures engines for a living hasn't heard of this on one of the most common motors on the road! And these guys are charging over $2k for a remanufactured stock motor - with my core exchange. Sure doesn't inspire confidence. I don't care if the heads are "still" in good shape, I've read enough about them I don't want to risk another set of Castech heads. I do see lots of L83 heads on Ebay (Gen V Ecotech motor?). I don't know about mixing and matching, etc. That's why I just jumped to buying "new" heads. I know that I know that I know I won't be getting Castechs.


You say in your area - where do you find them? I'm not 'plugged in' I guess to the scene, a lot of these things seem to be word of mouth, I think. I don't do FB, either, I've been told "You can get a motor on FB for next to nothing" but I purposely stay away from that platform and would rather continue to do so.

I see a "racing" LS9 cam kit on Ebay for around $400, or just a camshaft with springs and seals for anywhere from $160-200. I think this would be an acceptable drop in upgrade. I don't want to overcomplicate things with having to have heads overbored or any of that, as it just means more people in the loop, have to drop parts at a machine shop and wait till they get around to doing the jobs, etc. Sort of like having too many cooks in the kitchen, another reason I thought going with new heads would make things simpler, if it was $100-200 more, I'm not on THAT tight of a budget. I just don't want to spend $4k on this.


That's cool, I'm not opposed to more power - I just don't want to overbuild it and spend a lot of money looking for more power, as I just didn't feel I needed it. I know how easily it can turn into a neverending money pit looking at the various add-ons for "moah powah!" But I get it, if it does more power and works easier, it will save fuel. For fuel, I usually use premium non-ethanol anyways. I have to run this in my 370Z and just always stuck with it in my Tahoe, as well.


If I'm correct, this would require other exhaust work, too, right? I don't think I want to have to redo the exhaust right now, although I would like to later, since it appears I'm going to be keeping this a long time. Better sound and flow, but I've got a lot on my plate right now - and tax time is also coming up. :( No stimulus checks OR tax refunds for this guy.


This is on a 2004. I've had it for 10+ years, bought it with about 83k, it's now at 275k miles. And I've put 70k or so on my 370Z since I bought it in 2013. I used to drive a LOT, the majority of those were pre-2018, since then I went from commuting 150 miles a day, to under 2 miles a day - round trip. Honestly, the Tahoe has been a great vehicle for me, the only real things I've ever had to do were routine maintenance. I did electric fans, replaced wheel bearings in one wheel, and have the problem with the blend door actuators and rear heat/AC which I cannot get to work right regardless of changing out the actuator. But in general, mechanically, it's been wonderful up to this point. Starting to have some niggly electrical stuff like seat motors, cruise control wonky, etc., but I really have loved my truck. If I can get it back on the road, then start to work on the little things myself, and I am thinking I'll need to do a trans sometime in the next 100k or so, too...

But I really REALLY don't want to take on a car payment again. So this is where I am.

Sorry if this is too longwinded.


No need to apologize for the novel! The more we know, the better we can help.

I don't do FB, either. I'm also not "plugged in" to the scene. Total loner here. However, I often use my GF's FB for MarketPlace cuz that's where the deals are. I "refreshed" my brother's '05 LM7 (same as yours, but not FlexFuel) a few years ago due to a Castech failure. He didn't want anything to do with that type of head and finding non-Castech 706/862s wasn't happening in our timeframe. He bought a set of low-mileage 799s from a 2010 and we slapped 'em on. You lose compression with these heads on an LM7, but he didn't care. We could've had 'em shaved, but we didn't have the time to get into push rod lengths, etc. He's been happy with it.

I mentioned "cloning" an L33 if you were doing a full-on rebuild and getting new pistons. It'd be all factory parts and with the flat top pistons, it'd be perfect with the ubiquitous 799/243 heads. Hint: Search for 799s since they don't have the cult following of the 243s, yet they're the same head. It's great that you're okay with running high octane. The stock L33, and pretty much any Gen4 engine really does better with 89 or higher. It's "fine" on 87, but the power and MPG loss is there. I'd say the hardest part of cloning an L33 would be finding the cam for less than the cost of a new performance (even very minimal) cam.

Keeping it as cheap as possible yet avoiding 706/862 heads, you could keep your stock cam and all and just get the 799/243s. You'll just have to either deal with the compression loss (loss of torque/efficiency) or swap in 4.8 pistons to complement those heads. My point was to touch on a little of all the aspects more power/efficiency and economy and budget.
 

Goebz

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SO I'm in th same but but bought a Jasper Crate motor instead. Ifti is a "level 1". ALL jaspers have the AFM/DOD delete and the level 1 gives you an upgraded cam. the DOD only nets 1 mpg improvement so not feeling like Im losing anything. Also went withe Headers and dual cat Y pipe as my Cats were giving me the rotten egg smell at 265k miles. They have the O2 sensor holes so should run well with computer.
GM53-07134300LSW American Racing.
Also decided on cold air since the Jasper ships with a Diablo tuner. It is required to run the AFM/DOD delete so I can also tune for the headers and Cold air. Figure I'll be at about 355HP without any significant remapping. I tow EVERYTHING so I thought it would be good to get the added torque. Will post when its don't to let everyone know.

IMG_8271.jpeg
 

1BADI5

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SO I'm in th same but but bought a Jasper Crate motor instead. Ifti is a "level 1". ALL jaspers have the AFM/DOD delete and the level 1 gives you an upgraded cam. the DOD only nets 1 mpg improvement so not feeling like Im losing anything. Also went withe Headers and dual cat Y pipe as my Cats were giving me the rotten egg smell at 265k miles. They have the O2 sensor holes so should run well with computer.
GM53-07134300LSW American Racing.
Also decided on cold air since the Jasper ships with a Diablo tuner. It is required to run the AFM/DOD delete so I can also tune for the headers and Cold air. Figure I'll be at about 355HP without any significant remapping. I tow EVERYTHING so I thought it would be good to get the added torque. Will post when its don't to let everyone know.

View attachment 274748

What are the specs on the cam?
 

fasteddy

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I don't know what year or how many miles are on your hoe, but if it over 150K you should replace pistons.
Then if you do
Just have the machine shop bore the block to 6.0L
you have to bore it anyway for new pistons.

Get yourself a set of remanned 862s and leave everything else the same
Good to go. You can even run the same cam and tune is optional. Recommended but optional.

If your hoe lives below 5000rpms and you want more TQ,
That's the best budget upgrade on a 5.3L rebuild.

BTR stage 1 cam would then be the next step up from there.
Then headers
Then TURBO! LOL Its really hard to find a turbo kit for 4WD hoes
 
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