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Thread: Getting nowhere on my issue...

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    99dart's Avatar
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    Default Getting nowhere on my issue...

    Are there any engine builders here that have run into this?? I have already asked several people about this issue. But, gotten no solid answers. A month ago know my son & I assembled a fresh .030 over 360 for his 98 black CC R/T. The rocker arm geometry is off. The pattern on the valve stem is to the outside (towards the headers). We used a length checker only to find out we couldn't go short enough on the push rods to get a good contact pattern. Now here's the kicker...my engine (360) has the same issue! I am running a 6.70" pushrod with Crower SS 1.7 rockers made for the Magnum engine. According to Crower they have 1.38" pivot to roller tip length. Nothing I inquired about in their catalog had a shorter arm. I am waiting on a return communication from PRW on the length of their rocker arm.Any insight into this issue would be MUCH APPRECIATED!!
    Pat
    99 DA CC R/T
    13.97@100 w/modded kegger & ported TB
    12.96 @103
    10:8-1 .30 over forged bottom end
    R/T ported heads
    Detroit locker 4:56 gears
    Built 46RE MSaine 3500 stall Ultra Billet
    http://imgur.com/a/lOVuZ

  2. #2
    niebs's Avatar
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    Default

    decked block or heads?

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    99dart's Avatar
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    My son's block was decked, new EQ heads. Mine was odd, looked decked already, .012 cleanup on heads after implosion. :/ Both at zero deck.
    99 DA CC R/T
    13.97@100 w/modded kegger & ported TB
    12.96 @103
    10:8-1 .30 over forged bottom end
    R/T ported heads
    Detroit locker 4:56 gears
    Built 46RE MSaine 3500 stall Ultra Billet
    http://imgur.com/a/lOVuZ

  4. #4




    slammedR/T's Avatar
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    My old 408 had had the block decked to zero around .010" and the Edelbrok heads cut done .030" to get the combustion chambers around 59cc and I still only ran a 6.950" pushrod.
    What lifters are you running?
    This signature has been deleted thanks to photobucket!

  5. #5


    99dart's Avatar
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    My kid has new Mopar lifters, I have a set of Danno modified (semi-solid)Mopar units.
    99 DA CC R/T
    13.97@100 w/modded kegger & ported TB
    12.96 @103
    10:8-1 .30 over forged bottom end
    R/T ported heads
    Detroit locker 4:56 gears
    Built 46RE MSaine 3500 stall Ultra Billet
    http://imgur.com/a/lOVuZ

  6. #6


    99dart's Avatar
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    0628181141.jpg
    Only the exhaust valves show any pattern at all on mine.
    99 DA CC R/T
    13.97@100 w/modded kegger & ported TB
    12.96 @103
    10:8-1 .30 over forged bottom end
    R/T ported heads
    Detroit locker 4:56 gears
    Built 46RE MSaine 3500 stall Ultra Billet
    http://imgur.com/a/lOVuZ

  7. #7

    98Dak408's Avatar
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    I’m not familiar with the Crower rockers but I did see a note that they may have a backset trunnion. If the hole in the trunnion is offset, then maybe spinning the trunnion 180-degrees will result in better alignment by pulling the rocker tip back?

    https://www.crower.com/catalogs?id=rockerarms

    What is the part number of your rockers?

  8. #8


    99dart's Avatar
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    73656P They did have roller guides, but I sent them in for removal and re-fresh.
    99 DA CC R/T
    13.97@100 w/modded kegger & ported TB
    12.96 @103
    10:8-1 .30 over forged bottom end
    R/T ported heads
    Detroit locker 4:56 gears
    Built 46RE MSaine 3500 stall Ultra Billet
    http://imgur.com/a/lOVuZ

  9. #9

    98Dak408's Avatar
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    The Crower catalogue on page 145 for those rockers specifies: "* Requires machine work"

    What machining did you have to do?

  10. #10
    9t9-5.2's Avatar
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    The valve springs and retainers do not fit each other properly. Look at how much of the spring isn't under the retainer. Also, the springs appear to be a tight fit at the recessed spring seat on the head.

    I don't see that having anything to do with your tip to tip issue.

    "Excuse me if I have some place in my mind, where I go time to time"

  11. #11
    9t9-5.2's Avatar
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    Quote Originally Posted by 98Dak408 View Post
    The Crower catalogue on page 145 for those rockers specifies: "* Requires machine work"

    What machining did you have to do?
    If you use the recommended stud, the pedestals have to be modified for the 7/16" bottom thread.

    I bought and installed a set of these back in 99 on my truck. At that time they came with a stud that matched the Magnum head pedestal thread and were 3/8" on the tops.

    "Excuse me if I have some place in my mind, where I go time to time"

  12. #12


    99dart's Avatar
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    Quote Originally Posted by 98Dak408 View Post
    The Crower catalogue on page 145 for those rockers specifies: "* Requires machine work"

    What machining did you have to do?
    I don't remember anymore. It's been 10-15 years since they were originally done.
    99 DA CC R/T
    13.97@100 w/modded kegger & ported TB
    12.96 @103
    10:8-1 .30 over forged bottom end
    R/T ported heads
    Detroit locker 4:56 gears
    Built 46RE MSaine 3500 stall Ultra Billet
    http://imgur.com/a/lOVuZ

  13. #13


    99dart's Avatar
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    Quote Originally Posted by 9t9-5.2 View Post
    If you use the recommended stud, the pedestals have to be modified for the 7/16" bottom thread.

    I bought and installed a set of these back in 99 on my truck. At that time they came with a stud that matched the Magnum head pedestal thread and were 3/8" on the tops.
    Mine are the original 5/16" bottom, 3/8' top. Actually have the same setup on my son's EQ heads as well.
    99 DA CC R/T
    13.97@100 w/modded kegger & ported TB
    12.96 @103
    10:8-1 .30 over forged bottom end
    R/T ported heads
    Detroit locker 4:56 gears
    Built 46RE MSaine 3500 stall Ultra Billet
    http://imgur.com/a/lOVuZ

  14. #14


    99dart's Avatar
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    Here's a follow up to my son's & my issue with rocker arm roller contact pattern. With his engine on the stand, my kid was able to "see" more clearly to play with different combo's. As it turns out our guide plates were way too thick for our application. He found a Comp Cams set that were much thinner that allowed the roller tip to pull back away from the outer edge of the valve stem.
    https://www.summitracing.com/parts/cca-4825-8/overview/
    99 DA CC R/T
    13.97@100 w/modded kegger & ported TB
    12.96 @103
    10:8-1 .30 over forged bottom end
    R/T ported heads
    Detroit locker 4:56 gears
    Built 46RE MSaine 3500 stall Ultra Billet
    http://imgur.com/a/lOVuZ

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