6.0 vs. 5.3 conversion questions

[mattt]

Had another idea since I am looking at sourcing the basis of my 6.0 build from a local pick your part. Would it behoove me to get the Denali or Escalade factory computer to swap into my Tahoe, which that could then preclude me from needing to get my stock 5.3 Tahoe computer tuned?

 

[Tonyrodz]

Had another idea since I am looking at sourcing the basis of my 6.0 build from a local pick your part. Would it behoove me to get the Denali or Escalade factory computer to swap into my Tahoe, which that could then preclude me from needing to get my stock 5.3 Tahoe computer tuned?

Not a bad idea, but it would need to be reflashed for your vin anyway.

 

[mattt]

Hmmm, really.....VIN has to match in order for the ECU to work correctly? I did not know that. Thanks for the info.

 

[bottomline2000]

Had another idea since I am looking at sourcing the basis of my 6.0 build from a local pick your part. Would it behoove me to get the Denali or Escalade factory computer to swap into my Tahoe, which that could then preclude me from needing to get my stock 5.3 Tahoe computer tuned?

Your gonna have issue with inspection since your vin will need to be on the ECM. Better to have it tuned with your original ECM. An 04+ Lq4 with beefier LS2 rods and floating wrist pins would be the way to go. You want more out of it add a cam, headers and other mods based on how you use it.

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[zraffz]

I'm actually getting ready to do this in my Tahoe. Correct me if I am wrong but the only thing you need to change to do this swap is the flexplate. You need to remove the 6.0 flexplate + spacer and install the 5.3 flexplate (I have heard talk about using the Silverado SS 6.0 flexplate) can anybody verify what is actually required?


In my case, I am swapping on my 5.3 intake/TB/fuel rails because my donor motor is a 2005 without the return fuel line and DBW TB.
And then obviously a retune.

 

[bottomline2000]

I'm actually getting ready to do this in my Tahoe. Correct me if I am wrong but the only thing you need to change to do this swap is the flexplate. You need to remove the 6.0 flexplate + spacer and install the 5.3 flexplate (I have heard talk about using the Silverado SS 6.0 flexplate) can anybody verify what is actually required?


In my case, I am swapping on my 5.3 intake/TB/fuel rails because my donor motor is a 2005 without the return fuel line and DBW TB.
And then obviously a retune.

Literally swap everything from your 5.3. The only time you will see the flat flexplate with spacer on a 6.0 is of its attached to a 4l80 and in that case take the 4l80 too lol. You may need it sooner than later. A 6.0 from a 1500 platform will have a 4l60 behind it..

In my case I have a dished 4l60 sfi rated flexplate connected to a 4l80. I used the same flexplate on my 4l60. The converter is cut for the 3 hole 4l60 pattern but splined for a 4l80. There are a lot of ways to skin a cat.

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[Tonyrodz]

Used my old 4.8 flexplate. No issues.

 

[zraffz]

Literally swap everything from your 5.3. The only time you will see the flat flexplate with spacer on a 6.0 is of its attached to a 4l80 and in that case take the 4l80 too lol. You may need it sooner than later. A 6.0 from a 1500 platform will have a 4l60 behind it..

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The LQ4 I have is from a 2500HD. Do I need to swap over the accessories (all I can tell is the alternator is a little bigger on the 6.0) and I assume the original 5.3/4L60E flexplate will work? I notice the SS 6.0/4L60E flexplate looks a bit different in design but remains curved like the 5.3/4L60E flexplate.

 

[Tonyrodz]

Mine also came from an 05 HD Silverado. My buddy did the actual swap for me. He used everything from the 05--except like you--the intake--due to the no return line.

 

[zraffz]

So swap flexplate, intake and starter... got it. I'm excited to start tearing apart this 6 liter. I've rebuilt 2 or 3 of them already and have been itching to build a motor but life has gotten in the way!

 

[deerhunter1970]

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?

No, it's a stock Yukon XL 1500 SLT. It has the GT5 option gears, ordered that way by my father-in-law. I'm not running big tires and wheels - 265/75/16 BFGoodrich All Terrain T/A KO2s, so it spins pretty fast on the highway, but it rarely ever kicks down out of 4th, even with a load on it. I really think that's how the original engine and trans lasted so long (471,000) as it didn't have to work so hard pulling the beast around.

 

[mattt]

No, it's a stock Yukon XL 1500 SLT. It has the GT5 option gears, ordered that way by my father-in-law. I'm not running big tires and wheels - 265/75/16 BFGoodrich All Terrain T/A KO2s, so it spins pretty fast on the highway, but it rarely ever kicks down out of 4th, even with a load on it. I really think that's how the original engine and trans lasted so long (471,000) as it didn't have to work so hard pulling the beast around.

Thanks. Learned something new today. When the original engine and trans gave up the ghost at 471k, was it catastrophic or just a slow dying death?

 

[deerhunter1970]

Thanks. Learned something new today. When the original engine and trans gave up the ghost at 471k, was it catastrophic or just a slow dying death?

Blew a head gasket after overheating due to a blown plastic heater hose connector! The trans was still in good shape, but since I was replacing the engine, figured I might as well do the trans too as a package.

Most everything else (axles, transfer case, alternator, etc.) is original and still working fine. I drive like an old person, gotta make this thing last as long as possible

 

[zraffz]

Most everything else (axles, transfer case, alternator, etc.) is original and still working fine. I drive like an old person, gotta make this thing last as long as possible

You're very fortunate lol. I assume front CV shafts have been changed? My old girl eats CV shafts annually cause of the lift.

 

[deerhunter1970]

As far as I know - they are original!!! I don't have any lift...if anything its lowered, as I'm sure the bars have sacked a little...

It needs shocks, but I'm hesitant to mess with it. I'm sure once I do, it will start breaking on me

 

[mattt]

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

One plus I thought of for using the 243/799 instead of having the cut 317's is the more the stock 6.0 head is cut, you could run into an issue with intake manifold fitment, as the heads become shorter, the distance between heads will grow larger.

 

[01FormulaTA]

One plus I thought of for using the 243/799 instead of having the cut 317's is the more the stock 6.0 head is cut, you could run into an issue with intake manifold fitment, as the heads become shorter, the distance between heads will grow larger.

.040 is the max you can go without running into issues

http://www.ls1truck.com/forums/powertrain/20902-milling-317-heads.html

https://www.performancetrucks.net/f...-modifications-158/mill-317s-how-much-431884/