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L83 Upgrades

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  • L83 Upgrades

    New to the forum, thank you for adding me. I have been reviewing a lot of the Gen V motor information in both the truck and the C7 forum. I have a lowered 2015 GMC Sierra SLE with a 5.3L that I have been slowly playing with. Click image for larger version

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    The truck already has the following:
    - Kook 1 7/8" headers with Y-Pipe and Racing Cats
    - 3" Super 40 Flowmaster Mufflers
    - K&N series 66 Intake
    - MSD 8.5mm Superconductor wires

    So here in lies my questions:
    -Looking at the L86 cylinder heads and knowing that they can bolt on, how much larger are intake and exhaust runners, and also the chamber volume?
    -Even though both motors run 11:1 compression, would I have to mill the heads a little to bump up the compression?
    -In addition to the heads, I assume that it would behoove me to also get the 6.2L intake and throttle body?
    -I was looking at the new Comp cams Gen V cams and it looks like I would need some better valve springs and pushrods to boot, would PAC1519 Springs and 7.40 Moly Rods do it?
    -Would there be anything else that would be suggested with the swap?
    -Does your shop do tuning for this sort of thing or would I have to research one?

    Any help would be greatly appreciated. And I would love to work with you guys to help improve my truck. I am not opposed to a supercharger, but I would like to see what I could do naturally aspirated first. Thank you.

  • #2
    L86 LT1 General Motors Cylinder Head Runner Volumes and Chamber Volumes

    The factory L86 LT1 cylinder heads runner volumes and chamber sizes are as follows.

    Stock L86 LT1 cylinder heads -

    297 CC intake runner volume / 107 cc exhaust , 56.5 cc chambers

    Lingenfelter CNC ported L86 LT1 cylinder heads -

    308 CC intake runner volume / 110 cc exhaust . 61 cc chambers before surfacing.

    With a camshaft change you would require better valve springs.

    We offer the following camshafts for the LT1 engine & the related spring kits are included on the item pages

    I would suggest checking the pushrod length during assembly. In most cases the stock pushrods can be reused (LT1)


    • #3

      Thanks Tim!

      How much are the CNC'd heads? I didn't find them in the shop.

      The camshafts look good and both are a bit of a more aggressive than comp cams. Would both still work with the AFM?

      Would I need the 6.2L intake and Throttle body for the swap? And would Lingenfelter be able to do the tune if I sent the ECM?


      • #4
        Lingenfelter CNC Ported L86 LT1 cylinder heads -

        The Lingenfelter CNC ported L86 LT1 cylinder heads can be bought outright or you can send your cylinder head cores in to have the work done. Expect about 7-10 day turn around.

        Here is a link to the Lingenfelter CNC ported LT1 L86 cylinder heads


        • #5
          Great. Looks like I'm getting a bit closer.

          For your camshafts, do they need the phaser limiter kit like the comp cams do?


          • #6
            Also, do you know how thick the head gaskets are?

            I talked to Texas Speed and a local shop but no one really knows or wants to do the digging. I noticed that the 5.3L head and 6.2L head have different gasket numbers, so will your heads bolt on and work on an L83? Do I need the 6.2L intake and throttle body to complete the package?

            If this stuff will work, then I will be placing my order with you.

            Lastly, if I removed the ECM, could you guys do the tune?
            Last edited by Crimson2015; 11-10-2014, 04:12 PM.


            • #7
              Any answers?


              • #8
                All of the Lingenfelter GT series camshafts will require the use of the phaser limiter CC5456 . We will need to set up a L86 cylinder head on a stock 5.3 L short block and see if it will work in regards to sealing, valve to cylinder wall & valve to piston clearance. Once we have this information I will post the results.
                Last edited by Tim@Lingenfelter; 12-12-2014, 12:34 PM.


                • #9
                  Thank you very much Tim. I look forward to the information you'll get.


                  • #10
                    Any updates on the L86 Head bolting up to an L83?


                    • #11
                      Actually yes. Since I couldn't get anyone to pull the gaskets and take a look to verify everything matched I ate the money and bought the two gaskets. The ONLY difference between the two gaskets it seems is the bore size for the L86. I still have to pull my micrometer out to measure the gasket thickness, but they look identical otherwise.

                      All in all, they will bolt on and you'd want the 5.3L head gaskets, but now the question lies with how much flow can you get out of the stock 5.3l heads versus the L86 heads. I'll be talking to a machinist to try to get some numbers.


                      • #12
                        I would like to know as well if the L86 6.2 heads will work on the 5.3 L83 heads.
                        Anyone figure this out yet?


                        • #13
                          I PM'd Tim on the head fit question.