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--