6.0 vs. 5.3 conversion questions

[mattt]

My 04 Tahoe just rolled 290k on original engine and trans. I'm considering a 6.0 replacement. Is it worth the effort to drop an LQ4 in there in place of my L59 5.3? Researching it, there isn't much Torque or HP difference between the 04-06 5.3's and the standard LQ4 6.0. The LQ9 definitely has more to offer. I was considering an L33, but dropped that idea for the same reasoning and due to the unfounded price premium an L33 brings.

Anyone here done an LQ4 conversion and felt the difference was worth it?

Another option I'm looking at is "making" an iron block L33 out of my existing 5.3. Has it been done previously, with flat top pistons and 799 heads? That combo would get me closer to an LQ4 output too.

Is there a definitive thread out there that covers all aspects of a 6.0 conversion? I searched and didn't come up with a definitive thread that covers all aspects.

With using a 6.0 longblock, can I bolt on my existing outer engine components and expect the computer being able to compensate for the additional cubes, air & fuel requirements?

 

[adriver]

Just curious, what are your goals? What is your budget? Is anything been done to your current engine? (you've got most of the what, but what about the why?)

 

[01FormulaTA]

Tons of threads covering this swap...but there’s really not much to cover...pull out 5.3 then put in the 6.0...they are physically the exact same size, the extra cubic inches come from the 4.00” bore, the 6.0 and 5.3 use the exact same crank and rods, all connections are the same and yes you will notice a difference, peak HP and TQ don’t tell the whole story, mod for mod the 6.0 will make more power everywhere under the curve, might as well do a cam too to get the most out of the swap

 

[Tonyrodz]

Tons of threads covering this swap...but there’s really not much to cover...pull out 5.3 then put in the 6.0...they are physically the exact same size, the extra cubic inches come from the 4.00” bore, the 6.0 and 5.3 use the exact same crank and rods, all connections are the same and yes you will notice a difference, peak HP and TQ don’t tell the whole story, mod for mod the 6.0 will make more power everywhere under the curve, might as well do a cam too to get the most out of the swap

Did it to my 03. Originally came with a 4.8, now has an 05 Lq4--cammed and tuned. Totally worth it.
On the ride home after the cam swap.

Morning start.

Having some fun.

Everything physically bolts in. Just put some money in the budget for a trans rebuild.

 

[SnowDrifter]

Oh my **** that cold start sounds amazing

 

[mattt]

Just curious, what are your goals? What is your budget? Is anything been done to your current engine? (you've got most of the what, but what about the why?)

I've considered selling this Tahoe and sliding into one with lower mileage, but with 290k on the ticker it's going to be a very hard sell. So I've decided to keep it and do some upgrades, improvements. The existing 5.3 runs good, but leaks oil like a sieve currently. I also band-aided either a cracked head or leaky head gasket not too long ago with Barrs Leaks. So while my existing 5.3 still runs fine, in the short term, it is needing some serious attention on multiple fronts.

My line of thinking here is, why dump the coin into improving/fixing the 5.3 when I can do the same but with a 6.0?? There is no replacement for displacement. Seems like the budget will be about the same whether I'm working with a 5.3 or 6.0. Nothing is done to the factory 5.3 in the Tahoe. Why???, because I can and there is virtually no difference in which power plant I dump the coin into.

 

[mattt]

Tons of threads covering this swap...but there’s really not much to cover...pull out 5.3 then put in the 6.0...they are physically the exact same size, the extra cubic inches come from the 4.00” bore, the 6.0 and 5.3 use the exact same crank and rods, all connections are the same and yes you will notice a difference, peak HP and TQ don’t tell the whole story, mod for mod the 6.0 will make more power everywhere under the curve, might as well do a cam too to get the most out of the swap

I have not found one "bible" all inclusive thread here that covers the swap. I've found lots of threads, but none with all of the info packed into one complete thread. Can you point me to the one complete "bible" thread for the 6.0 swap?

I understand that they are physically the same and will drop right in, but there are differences between a LQ4 and LQ9. Is it worth the premium in procuring the 6.0 LQ9 over the less expensive LQ4. The difference in pistons and possibly rotating assy is all I have found being different which changes the CR. Do both the 4 and the 9 use the same "317" head?

I'm not sure I can get away with a cam swap since I'm in Demonrat ******-fornia where I have to have bi-annual smog checks.

 

[mattt]

Did it to my 03. Originally came with a 4.8, now has an 05 Lq4--cammed and tuned. Totally worth it.
On the ride home after the cam swap.

Morning start.

Having some fun.

Everything physically bolts in. Just put some money in the budget for a trans rebuild.

Did you retain the stock LQ4 dished pistons?

Was a flash/tune an absolute necessity or does the 5.3 stock ECM have enough flexibility to compensate for the additional load of more cubes, and more fuel/air demand?

And yes, with the engine out, I would definitely budget for a trans refresh at the same time since it's easily accessed at that point. Trans is 290k original too, but it doesn't leak and still shifts very good.

 

[HiHoeSilver]

I have not found one "bible" all inclusive thread here that covers the swap. I've found lots of threads, but none with all of the info packed into one complete thread. Can you point me to the one complete "bible" thread for the 6.0 swap?

I understand that they are physically the same and will drop right in, but there are differences between a LQ4 and LQ9. Is it worth the premium in procuring the 6.0 LQ9 over the less expensive LQ4. The difference in pistons and possibly rotating assy is all I have found being different which changes the CR. Do both the 4 and the 9 use the same "317" head?

I'm not sure I can get away with a cam swap since I'm in Demonrat ******-fornia where I have to have bi-annual smog checks.

Curious what @swathdiver says to this ...

 

[Tonyrodz]

Did you retain the stock LQ4 dished pistons?

Was a flash/tune an absolute necessity or does the 5.3 stock ECM have enough flexibility to compensate for the additional load of more cubes, and more fuel/air demand?

And yes, with the engine out, I would definitely budget for a trans refresh at the same time since it's easily accessed at that point. Trans is 290k original too, but it doesn't leak and still shifts very good.

Yes, I still have the stock Lq4 pistons. Cam, pushrods and beehive springs are the only internal mods done. When any mods are done--to any LS motor--to get the most out of said mods, always best to do a reflash/tune of the pcm. Imo, you'd be able to "get by" on your 5.3 tune, but I think it would be best to tune the 6.0. Even if you do a stock 6.0 tune reflash. My Lq4 has the 317 heads. Pretty sure the rotating assemblies are the same between the 2, but not positive. Imo, unless you get a great price on an Lq9, it isn't worth the extra $$ for the 9. The 9 also calls for premium only, so something else to think about.
Granted--with the upgraded motor and trans--

 

[swathdiver]

Curious what @swathdiver says to this ...

I was waiting for Tony to chime in! He's done it, I've only read about it!

The LQ4 and LQ9 share the same camshaft, I believe their difference lies in the tune and the flat top pistons which increases compression from 9.4:1 to 10:1. This should not require premium fuel, the L33 and early Gen IV LC9 are also about 10:1 and do not require 91 octane.

One would have to weigh their options based on what's available, is it less expensive to get an LQ4 and drop some flat top pistons in it or buy an LQ9?

Like anything, a budget determines how fast you can go.

 

[01FormulaTA]

I have not found one "bible" all inclusive thread here that covers the swap. I've found lots of threads, but none with all of the info packed into one complete thread. Can you point me to the one complete "bible" thread for the 6.0 swap?

I understand that they are physically the same and will drop right in, but there are differences between a LQ4 and LQ9. Is it worth the premium in procuring the 6.0 LQ9 over the less expensive LQ4. The difference in pistons and possibly rotating assy is all I have found being different which changes the CR. Do both the 4 and the 9 use the same "317" head?

I'm not sure I can get away with a cam swap since I'm in Demonrat ******-fornia where I have to have bi-annual smog checks.

As far as a “Bible Thread” I doubt you are going to find a thread where anyone has written step by step, bolt by bolt instructions. If there’s a specific issue or problem you run into or something specific you are worried about just post the question and I’m sure someone will be able to chime in and help bc it’s a common swap. Again all you do is pullout your 5.3 and installing the 6.0 is as easy as doing the reverse steps of the removal. Here are a couple threads I pulled up after a quick search (I haven’t read through them so I don’t know which one will be most helpful to you)

https://www.performancetrucks.net/forums/projects-gallery-189/project-rebel-yell-552978/

https://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/lq9-swap-complete-364119/

https://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/lm7-lq9-swap-535092/

https://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/5-3-lq4-swap-464240/

https://www.performancetrucks.net/f.../lq4-swap-build-thread-2000-silverado-453821/

https://www.performancetrucks.net/forums/gm-engine-exhaust-performance-21/my-5-3-6-0-swap-472673/

As far as differences bw the LQ4/9...the LQ4 has dished pistons and lower compression, LQ9 has flat top pistons for higher compression. They use the same block, crank, rods, and both have 317 heads and use the same intake manifold. If you are not going to do a cam swap I would try to find an LQ9 to get the flat top pistons for the better compression.

If you do get an LQ4 make sure it’s an 01+...the early 99/00 LQ4 had Iron Heads and a 0.400” Longer Crankshaft that won’t work with your application

Even better if you could get an 04+ LQ4/9 as GM changed over to the beefier gen4 type bushed floating wrist pin connecting rods, 01-03 came with gen3 "ls1" type pressed wrist pin rods, but don’t let this scare you off from an 01-03, just nice to have the better rods if you go with a power adder down the road...

Gen 4 Rods (Left) vs Gen 3 Rods (Right)

 

[adriver]

Heres one I had bookmarked if this helps.
http://chevythunder.com/LS1 components.htm

looks like 99/2000 LQ4 was different.

 

[mattt]

Thank you TonyRodz, swathdiver, 01Formula, & adriver for all of the excellent commentary and tech info. Some of it I was aware of, but it's always good to go back over it.

One thing I've been considering is picking up an LQ4 because they don't bring the premium like LQ9's and then doing a head swap to bump the compression up. Has anyone tried this option yet, like swapping to a set of 799/243 heads which have a slightly smaller chamber vs. the 317 stock 6.0 heads?

I've seen quite a few Denali's drop recently at my local pick your part yards, which those have the LQ4. For the cost to get it out the gate, it leaves plenty of budget on the table to go thru it, check everything, and do a head swap. I just missed an 04 Denali earlier this week, went to check it yesterday and the engine was already gone.

It sounds like there is universal agreement to not bother with freshening up my 290k 5.3 that the Tahoe came with and just source a 6.0 to drop in it's place? The build cost is virtually no different between a 5.3 or 6.0 from what I see.

One more tech question I haven't ran down the answer on yet....is the intake manifold the same between a 5.3 truck and a 6.0 truck engine or is there a difference? Reason I ask is I'll probably just purchase a long block 6.0 and then swap over everything else from the stock 5.3.

Thank you all again.

 

[Tonyrodz]

Thank you TonyRodz, swathdiver, 01Formula, & adriver for all of the excellent commentary and tech info. Some of it I was aware of, but it's always good to go back over it.

One thing I've been considering is picking up an LQ4 because they don't bring the premium like LQ9's and then doing a head swap to bump the compression up. Has anyone tried this option yet, like swapping to a set of 799/243 heads which have a slightly smaller chamber vs. the 317 stock 6.0 heads?

I've seen quite a few Denali's drop recently at my local pick your part yards, which those have the LQ4. For the cost to get it out the gate, it leaves plenty of budget on the table to go thru it, check everything, and do a head swap. I just missed an 04 Denali earlier this week, went to check it yesterday and the engine was already gone.

It sounds like there is universal agreement to not bother with freshening up my 290k 5.3 that the Tahoe came with and just source a 6.0 to drop in it's place? The build cost is virtually no different between a 5.3 or 6.0 from what I see.

One more tech question I haven't ran down the answer on yet....is the intake manifold the same between a 5.3 truck and a 6.0 truck engine or is there a difference? Reason I ask is I'll probably just purchase a long block 6.0 and then swap over everything else from the stock 5.3.

Thank you all again.

Intakes are all the same for 4.8, 5.3 and 6.0's. That also includes the throttle bodies, as long as you stay with dbw or dbc.

 

[01FormulaTA]

Thank you TonyRodz, swathdiver, 01Formula, & adriver for all of the excellent commentary and tech info. Some of it I was aware of, but it's always good to go back over it.

One thing I've been considering is picking up an LQ4 because they don't bring the premium like LQ9's and then doing a head swap to bump the compression up. Has anyone tried this option yet, like swapping to a set of 799/243 heads which have a slightly smaller chamber vs. the 317 stock 6.0 heads?

I've seen quite a few Denali's drop recently at my local pick your part yards, which those have the LQ4. For the cost to get it out the gate, it leaves plenty of budget on the table to go thru it, check everything, and do a head swap. I just missed an 04 Denali earlier this week, went to check it yesterday and the engine was already gone.

It sounds like there is universal agreement to not bother with freshening up my 290k 5.3 that the Tahoe came with and just source a 6.0 to drop in it's place? The build cost is virtually no different between a 5.3 or 6.0 from what I see.

One more tech question I haven't ran down the answer on yet....is the intake manifold the same between a 5.3 truck and a 6.0 truck engine or is there a difference? Reason I ask is I'll probably just purchase a long block 6.0 and then swap over everything else from the stock 5.3.

Thank you all again.

The 317s are similar to the 243/799s, they have the same intake port design, the same size intake and exhaust valves, only difference is 71cc combustion chamber vs 64cc combustion chamber...you can pull the 317 heads and have them milled at a machine shop...every .006~1cc so you could have them milled ~.040 to get down to a 64cc combustion chamber instead of buying another set of heads

 

[mattt]

Thanks 01. I may look at that option too. I thought I had previously read though that the 243/799 are a better flowing cylinder head.

Does anyone know off the top of their head, what size in CC is the dish of the LQ4 pistons?

 

[01FormulaTA]

Thanks 01. I may look at that option too. I thought I had previously read though that the 243/799 are a better flowing cylinder head.

Does anyone know off the top of their head, what size in CC is the dish of the LQ4 pistons?

-6.7 CC Dish Pistons...

They flow nearly the same....

Flow data (317 Heads)
Lift In. Ex.
0.050 33.3 24.5
0.100 63.4 54.2
0.200 144.1 103.8
0.300 200.2 142.5
0.400 234.6 167.9
0.500 241.7 183.1
0.600 243.3 193.7
0.650 244.8 195.1

Flow Data (243/799 Heads)
Lift In. Ex.
0.050 31.1 24.7
0.100 65.4 52.6
0.200 142.2 98.1
0.300 193.5 133.5
0.400 230.2 160.1
0.500 243.4 175.5
0.600 248.1 185.8
0.650 249.3 188.2

http://www.superchevy.com/how-to/en...numbers-from-our-stock-ls-cylinder-head-test/

 

[deerhunter1970]

I did the swap on my '02 Yukon XL. The original 5.3 had 471,000 on it when it finally died. Bought a LQ4 longblock from Powertrain Products, along with their install kit. Has a 5 year unlimited mileage warranty. I'm 2 years and 24,000 miles in so far. My original motor was a FlexFuel, so the injectors are already bigger. I swapped over everything from the old motor (intake, TB, etc.). I sent also my PCM to BlackBear for a tune. I also replaced the trans with a Stage 3 unit from Transbuilderguy. It has a good bit more low to midrange grunt than the 5.3 had, which is good, as I regularly tow a 8,000lbs tractor.

Only one gripe so far - my mileage has gone down to about 12-13MPG from what was about 16. Probably due to the stock 4.10 gears spinning the larger engine @ 2000 RPM at 60MPH

 

[mattt]

Thank you for the real world experience deerhunter1970! Are you a 3/4T with the 4.10 gear? I didn't think 4.10 gears were available in the 1/2T truck/suv? Or did you change to 4.10 to compensate for tire size larger than stock?