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  • roller rockers on vortec heads

    i have vortec heads on my 350 engine with the stock rocker arms. my cam is .480 lift cam on intake and exhaust and i would like to know what the best combination of roller rockers arms i should use? 1.6 on intake and exhaust or 1.5 intake with 1.6 on exhaust? thanks in advance for the input.

  • #2
    Re: roller rockers on vortec heads

    first, are these stock vortec heads?
    whats the application?
    modified springs?
    modified valve guides?

    airdeano
    2001 Silverado 4.8L 4-spd Automatic 3.42
    ? horsepower
    ? torque
    will find out soon!

    1965 C10 5.3L (SSR) TH4L60e
    (It's Alive! 07/04 It Drives! 03/05 Daily Driver XX/08!)

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    • #3
      Re: roller rockers on vortec heads

      I'm sure you'll know you need the self alighning rockers. I run Scorpion full rollers, and they are perfect. I have no problems with them.

      Assuming your heads have NOT been modified, you are over their limit, if not cutting it close.

      However, if they are modified, I would use 1.6 on the exhaust, and 1.5 on the intakes.
      http://www.myspace.com/joe87montess

      2004 Silverado :read:
      1987 Monte Carlo SS 383 ci.
      1985 S10 Tahoe 350/TH350 4.10's and a mini spool

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      • #4
        Re: roller rockers on vortec heads

        i dont mean to jac your post but im interested as well cause i will be going with a set as well when i get some vortecs installed this summer. I didnt know that you can mismatch rockers so id like some clarifying on this subject. I thought they had to match such as 1.6 and 1.6 as apposed to 1.5 and 1.6 on the same head. What performane difference does this do? I was gonna go with just some 1.6s but is there an advantage with going with an ofset like you guys are talking about? Thanks before and bump for a good post.
        91' RCSB Red Silverado on a 4/6 with Custom 355 ( .449 .456 212 218 112), Tbi mods, 65lb inj. /flowtech headers, 2.5 40-flowmaster,Tuned W/EBL Flash,Custom Bench http://www.cardomain.com/ride/2059169?poll_action=view

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        • #5
          Re: roller rockers on vortec heads

          The 1.6 on the exhaust will allow for more lift, meaning more flow, since that valve is smaller. You've just got to make sure your Vortec heads are modified for the larger lift.
          http://www.myspace.com/joe87montess

          2004 Silverado :read:
          1987 Monte Carlo SS 383 ci.
          1985 S10 Tahoe 350/TH350 4.10's and a mini spool

          Comment


          • #6
            Re: roller rockers on vortec heads

            Originally posted by Joe87monteSS
            I'm sure you'll know you need the self alighning rockers. I run Scorpion full rollers, and they are perfect. I have no problems with them.

            Assuming your heads have NOT been modified, you are over their limit, if not cutting it close.

            However, if they are modified, I would use 1.6 on the exhaust, and 1.5 on the intakes.
            JoeMonte,
            Are the Scorpions self-aligning rollers? Mind telling me what part number they are? Thanks.
            97ChevyECSB,350,Dropped,All Poly,RearSwayBar,Headers,Flow50s,ZZ4Cam,ZEX,Nelson Hot Tune,915Beehives,1.6rollers,
            Port,Polish+Bowlblend,TBmods,plenumspacer,CAI,
            Built60E,3000stall,Transgo,MegaShifter+more.
            2004 Chevy CCSB 4x4 w/ K+N F.I.P.K, more to come
            1972 Pontiac LeMans 406cid

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            • #7
              Re: roller rockers on vortec heads

              i did forget about the modification of the heads. what has to be done to them to allow more lift? is it something that can be done with them on the engine or must they be pulled? As far as springs go they have the z28 valve springs on them.

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              • #8
                Re: roller rockers on vortec heads

                Originally posted by Joe87monteSS
                The 1.6 on the exhaust will allow for more lift, meaning more flow, since that valve is smaller. You've just got to make sure your Vortec heads are modified for the larger lift.
                Yeah i defiantely will get vortec heads with upgraded springs as i have a 449/456 camshaft already and was planning on going with bigger rockers. How would the lift from 479/486 with both 1.6/1.6 change if i were to put 1.6 on the exhaust and 1.5s on the intake? Would this give me more lift overall or just on the exhaust but not on the intake?
                91' RCSB Red Silverado on a 4/6 with Custom 355 ( .449 .456 212 218 112), Tbi mods, 65lb inj. /flowtech headers, 2.5 40-flowmaster,Tuned W/EBL Flash,Custom Bench http://www.cardomain.com/ride/2059169?poll_action=view

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                • #9
                  Re: roller rockers on vortec heads

                  The Vortec heads dont flow very well compared to the intake. installing the 1.6's can help this a bit, as well as larger valves and porting.

                  You can fit well ober 0.500" of lift on a vortec L31 head with no machining by using Compcams Beehive springs and retainers. These were originally built for LS1 use, but if you use the Compcams GEN1-E retainers(LS1 has different diameter valvestems).
                  Springs are 26915 or 26918, installed heights are 1.8" for both, tehse springs are much better than the LT4 springs, although teh Beehives are quite pricey.
                  If you dont want to pull the heads but want a higher lift cam with Vortec heads, its an option for sure.

                  You need to pull the heads to elongate the stock pushrod hole as the 1.6:1 rockers bring the pushrod closer to the fulcrum(pivot) and will cause the pushrod to rub in the head.
                  The vortecs like at least 10 degree in split between the intake and exhaust durations. I really like the LT4 Hotcam that is 218°/228° duration at 0.050" with 0.525"/0.525" on an 112°LSA.
                  The lift comes down to 0.497" with the 1.5:1 rockers.

                  peace
                  Pauly
                  97 GMC 2wd RCSB 5.7, s10 2700 footstall, Hooker 24621hkr LT's , 2.5" cats dual 4"pipes exit B4 pass. side tire, custom driveshaft 3.42 G80 FIPK MAF descreen GM/Mercruiser Marine intake manifold 29lb LS2(EV6) injectors Ed Wright PCM(best mod), LT4 KM 14.8@94mph 2.007 4000lbs 122mph

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                  • #10
                    Re: roller rockers on vortec heads

                    http://www.flatlanderracing.com/scor...chevySelfAlign

                    Theres a list of part numbers.

                    The heads need to be off the engine when doing that mod. I believe they cut the spring pockets, and trim the valve guides.
                    http://www.myspace.com/joe87montess

                    2004 Silverado :read:
                    1987 Monte Carlo SS 383 ci.
                    1985 S10 Tahoe 350/TH350 4.10's and a mini spool

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