L83 intake manifold swap

07Softail · December 14, 2016

Yeah, lt1 would need a custom fabbed intake. That's too severe of an angle to try and make work with the air box. L86 intake it is for me then lol

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PMed you

RT

Kenny Daigle · March 21, 2017

Does anyone have a l86 intake manifold and throttle body for sale?

MattM2485 · March 21, 2017

Does anyone have a l86 intake manifold and throttle body for sale?

You can get both from pace performance for under $250

JRoyPDX · July 31, 2017

Correct me if I am wrong, but I just went on 2 GM parts lookup sites and it lists the same intake manifold for both L83 and L86

EDIT - Don't trust those I guess. Pace Performance lists 12639087 and those lookup websites say they do fit the 6.2 Silverado. Retarded.

I looked up a 2017 Silverado LT 5.3 and got these part numbers:

Intake - 12623417

Throttle body - 12617792

I looked up a 2017 Silverado LTZ 6.2 and got these part numbers:

Intake - 12623417

Throttle body - 12620263

Only the TB lists differently. Just to be sure I looked up the same on a 2014 as well. If they are the same I hope nobody is wasting their money on swaps...

Edited July 31, 2017 by JRoyPDX

Txjose · August 1, 2017

The AFE intake will work with the LT1 or MSD manifold since you can swivel the tube on the box. I had to cut the end of mine off and use a new coupler but it worked fine other than that.

got a picture of it?

408LSX · August 1, 2017

Correct me if I am wrong, but I just went on 2 GM parts lookup sites and it lists the same intake manifold for

EDIT - Don't trust those I guess. Pace Performance lists 12639087 and those lookup websites say they do fit the 6.2 Silverado. Retarded.

I looked up a 2017 Silverado LT 5.3 and got these part numbers:

Intake - 12623417

Throttle body - 12617792

I looked up a 2017 Silverado LTZ 6.2 and got these part numbers:

Intake - 12623417

Throttle body - 12620263

Only the TB lists differently. Just to be sure I looked up the same on a 2014 as well. If they are the same I hope nobody is wasting their money on swaps...

They are different, I just did the swap yesterday. The L83 has an 80mm tb and the L86 uses 87mm tb. The opening on intake is clearly bigger.

Edited August 1, 2017 by 408LSX

JRoyPDX · August 2, 2017

They are different, I just did the swap yesterday. The L83 has an 80mm tb and the L86 uses 87mm tb. The opening on intake is clearly bigger.

How were your results?

408LSX · August 2, 2017

How were your results?

Seems to pull harder up top and throttle response seems better. I still need to get it retuned also.

L86 All Terrain · August 8, 2017

Would the engine even account for the swap without tuning? The ECU controls a/f, so without accounting for the ability to use more air and in-turn fuel, would the engine operate as normal? Or would the computer realize it has more air availble and adjust itself over time? I assumed no gain would be noticed, but dyno results prove a CAI with no tune can help or hurt gains. I know it was a popular mod to put LS7 TBs on gen III-IV's but most people were tuning for it. Curious to see your results if you can get it on a dyno for a baseline and tuned pull.

Edited August 8, 2017 by L86 All Terrain

JRoyPDX · August 8, 2017

Would the engine even account for the swap without tuning? The ECU controls a/f, so without accounting for the ability to use more air and in-turn fuel, would the engine operate as normal? Or would the computer realize it has more air availble and adjust itself over time? I assumed no gain would be noticed, but dyno results prove a CAI with no tune can help or hurt gains. I know it was a popular mod to put LS7 TBs on gen III-IV's but most people were tuning for it. Curious to see your results if you can get it on a dyno for a baseline and tuned pull.

It should see the additional air and adjust for its pre-programmed fuel trims so in theory you should see some difference in it. Tuning will of course net the best results.