1. rod7515

    rod7515 Well-Known Member

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    I have a 360 stroked to 408 that is running a comp cam .575, .575 lift and .308,.308 duration. Currently i am running 1.5 rockers and I am considering going to 1.6 rockers. Was wondering how to figure what the additional lift would be if I were to make this change. Also how much if any would that change the duration. I am also thinking of changing my 915 slightly ported heads to my edelbrock aluminum heads at the same time. I know either way i will need to check valve clearance with or without the rocker change if I do the head swap.
    Thanks Rod
     
  2. RammerJammer75

    RammerJammer75 Well-Known Member

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    Take .575 and divide it by 1.5 = .383
    Now multiply .383 by 1.6 = .613
    I believe it adds some duration, but I honestly don't know if it's enough to even notice. I've always been under the belief it might be a degree or 2.
     
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    • yellow rose

      yellow rose Overnight Sensation

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      Take your lift and divide by 1.5 which is .383, so you have a .383 lobe.

      Take your .383 lobe and multiply that by 1.6 and your new lift would be .613.

      I’m not sure of how to exactly figure how much more duration you’ll get, but the math smart guy’s probably can. I say you’ll pick up 2 degrees at .050 but don’t hold me to that.
       
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      • yellow rose

        yellow rose Overnight Sensation

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        DAMN.......TREED HARD.
         
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        • RammerJammer75

          RammerJammer75 Well-Known Member

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          You almost got it. You gotta be quicker than that :rofl:
           
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          • RustyRatRod

            RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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            I vote don't do it. It already has a lot of lift. You'll likely gain nothing.
             
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            • TT5.9mag

              TT5.9mag Two atmospheres are better than one

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              Not being a smart as Rob but,

              He gave no other useful information. How do you come to that conclusion?
               
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              • TT5.9mag

                TT5.9mag Two atmospheres are better than one

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                If it’s 13:1 with ported trick flows and under cammed I’d say he’d pick up some power.
                 
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                • rumblefish360

                  rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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                  It’s generally accepted that it is a 2* duration gain. Actual may vary.

                  The thing with your Edelbrock heads are there rated to be good to .575 lift. What I would do is disassemble the valve springs and see what’s under them. Get a valve height mic and start fishing around on springs to use that will for certain handle that lift.

                  IF you can not get the spring in with clearance on lift & you have only 1 thin shim under the valve springs (to protect the aluminum from the steel spring eating it up) look to possibly use a valve seat/stem cutter to drop the seat slightly. There isn’t much room to cut under the spring so be careful.

                  Porting the head would be next in line. IMO, for myself, maybe not you? I’d probably have a pro head porter on it to do both jobs.
                   
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                  • Garrett Ellison

                    Garrett Ellison Amateur driver on public roadway, do not imitate.. FABO Gold Member

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                    You said ported J heads, got any flow numbers from a flow bench for your porting job? I haven’t looked at modified J head flow numbers in a while, but I imagine it takes a lot of work for them to need .600 lift.
                     
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                    • RustyRatRod

                      RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                      It's just my humble opinion that he has a decent amount of lift......I think he would be better off making a completely different camshaft choice, but that's not what he asked, so I answered his question. Had he a dual pattern camshaft maybe around .550 lift, I would have voted "yeah".
                       
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                      • RustyRatRod

                        RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                        Right. IMO it's already over cammed."ESPECIALLY" with a single pattern camshaft and J heads. Even ported.

                        @MOPAROFFICIAL come see what you think.
                         
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                        • rumblefish360

                          rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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                          My 2 cents is to much cam on low flowing cylinder heads. On the cylinder head it is ether what I said or get a set of Trick Flows & 1.6 rockers. Sell the Edelbrock & J heads to roll the money over into the Trick Flows.
                          (That’s the best move IMO)
                           
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                          • RustyRatRod

                            RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                            I ain't disagreein. It'll run good like it is, it's just not what you might consider "optimal"......but then, how many builds ARE, you know?
                             
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                            • TT5.9mag

                              TT5.9mag Two atmospheres are better than one

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                              Sounds logical Rusty. I have no idea how I read past “slightly ported J heads” and the mention of edlebrocks. But I did. I will say this though, typically I measure valve to piston clearance and run as much lift as I can. But I like a lot of lift.
                               
                            • rumblefish360

                              rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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                              That word “optimal” is arguable. It’s the driver that must be satisfied. To that end I say the word optimal equals rarity and satisfaction is per the drivers desires.
                              :p

                              Agreed, so long as the head supports it, YUP! Though not every build will need it or utilize it. Much depends on what is being done with the engine & car.
                              :steering:
                               
                            • RustyRatRod

                              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                              I agree completely. What's "optimal" for one may not be for another. Whatever makes you happy.....maybe that's a better phrase.
                               
                            • RustyRatRod

                              RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                              I agree! I like a lot of lift, too. But stock heads run out of steam before .500 lift. His are ported.....but how much more does that really add? If he had W2s or maybe trick flows or eddys......then it's a different ball game.
                               
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                              • jay27

                                jay27 Well-Known Member

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                                I have used that cam with a 10.1 360 with ported x heads , I did not have them flowed but it was very strong , shifted at 7000 - 7200. Worked well in my application , I would not have bothered with 1.6 rockers personally but each to their own.
                                 
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                                • rod7515

                                  rod7515 Well-Known Member

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                                  First let me thanks for all the replys and thoughts. I thought I would share some addition information on this motor. It has about 300 miles on it. As I said its stroked and is .040 bore. Compression right now is at 10.5-1. I expect to go to 11.5-1 with the aluminum heads??? I am going to include some pics of the porting that has been done. I bought these heads already ported and had the hardened seats added and 2.02 / 1.88 valves. I did not have these flow tested nor am I going to but I would guess they should flow fairly well for 915 heads as close as appear to be worked. After looking at the cost of new rockers if i would want more lift it would probably be less expensive to go with a different cam?? So probably i will just have to be satisfied with my 1.5 rockers and just do the head swap. I will also be putting on my 2x4 set up (if it fits under the hood scoop) when i do this change. Again thanks for all your thoughts. Its greatly appreciated.
                                  Rod
                                   
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                                  • rumblefish360

                                    rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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                                    We’re the J heads ported for this engine?
                                    If so, bolt them on, check clearances, go have fun!
                                     
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                                    • rod7515

                                      rod7515 Well-Known Member

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                                      My pics didn't post so when I get home here shortly I will try again to post head pics. Rumble. I boight these heads already ported so I didnt know what I had until they showed up.
                                      Rod
                                       
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                                      • Garrett Ellison

                                        Garrett Ellison Amateur driver on public roadway, do not imitate.. FABO Gold Member

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                                        Sure does sound like a fun ride!
                                         
                                      • rod7515

                                        rod7515 Well-Known Member

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                                        Here are pics of the heads. They didnt attach on last attempt. DSC04962 (Copy).jpg DSC04961 (Copy).jpg DSC04960 (Copy).jpg DSC04957 (Copy).jpg DSC04956 (Copy).jpg DSC04955 (Copy).jpg DSC04954 (Copy).jpg
                                         
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                                        • Wyrmrider

                                          Wyrmrider Well-Known Member

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                                          you would have to flow them to tell
                                          running open headers or through the mufflers?
                                          I doubt slightly ported could use .600 lift
                                          does the duration give you the rpm range you want?
                                          how about a pic of a stripe on the top of the valve stem
                                          you may need a b3 kit
                                          or change heads
                                          the TF heads do not usually need a b3 kit so include that in the price info
                                           
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