[DeTomaso] Rocker Arms

doug351c doug351c at gmail.com
Tue Mar 10 00:46:43 EDT 2015


Brian,

I had a wrong dimension for the pushrods in my first email.  I meant to say that you have to be careful when you use 3/8" dia pushrods which are larger than the stock 5/16" pushrods.  
It's not the 7/16" studs that cause the rocker binding problem with high lift cams.  Most every roller rocker has plenty of rocker stud clearance for high lift cams.  But not all of them are properly clearanced for use with larger diameter pushrods when using high lift cams.  The side of a larger 3/8" diameter pushrod can bind against the backside of the rocker body at near full lift.  

Doug Braun
blue 73L #5505   
  -----Original Message-----
  From: Brian Dudley [mailto:bd8134 at gmail.com]
  Sent: Monday, March 09, 2015 12:28 PM
  To: doug351c at gmail.com
  Cc: mark skwarek; Tony DiGiovanna; detomaso
  Subject: Re: [DeTomaso] Rocker Arms


  As per George Pence's sticky..
  "If your motor’s cylinder heads are milled and tapped for 7/16” stud & guide plate type rocker arms the Yella Terra YT-6321 rocker arm is the hot tip. This very rugged rocker arm also performs like a shaft mounted rocker arm therefore it requires no studs, guide plates or hardened push rods. Internet pricing for the Yella Terra YT-6321 rocker arm is in the range of $650 US dollars for a set of 16, sometimes even lower. That may look "pricey" up front when compared to the standard push-rod guided arm, but they don't require studs, guide plates, poly-locks or heat treated push-rods. Once you add up the price for a set of conventional roller rocker arms plus all the additional stuff you need the price difference is not that bad ... some guys feel it is break-even."
  I am using these with a solid cam with the same lift.
  Stock valve cover fits.
  Using a rocker that you have to modify sounds like it is designed for a lower lift.


  On Sun, Mar 8, 2015 at 10:49 PM, doug351c <doug351c at gmail.com> wrote:

       i>>?

       Yep Mark - that can't be empahsized too much.  That's why I said the
       backside may need to be clearanced. (it bit me too !!!)



       Doug

       -----Original Message-----
       From: mark skwarek [mailto:ehpantera at yahoo.com]
       Sent: Sunday, March 08, 2015 6:34 PM
       To: doug351c at gmail.com; Tony DiGiovanna; detomaso at poca.com
       Subject: Re: [DeTomaso] Rocker Arms

       Just make sure that you have clearance between the pushrod and the
       rocker base at full lift. Under high lift the pushrod can make contact
       with the base of the rocker arm. Them the end of the rocker arm end
       will break off. Been there, done that.
       Mark
       On Sunday, March 8, 2015 9:48 PM, doug351c <doug351c at gmail.com> wrote:
       I like the Scorpion Endurance SCP3023 1.73:1 forged aluminum roller
       rockers.
       They have a hardened insert seat, the shaft is centerless ground, a
       7/16"
       poloc nut is included and they have a great lifetime warranty.  $326 a
       set
       at Summit Racing.
       Max spring dia = 1.625"
       [1]http://www.summitracing.com/parts/scc-scp3023bl
       I'm running these on my 70 Cleveland Mach1 engine.  Please note though
       that
       if you intend to run 7/16" dia pushrods, their backsides need to be
       clearance for them.  Scorpion's Endurance series cost more than the
       Race
       series but they have a narrower body and shorter polylocks so they fit
       better under stock rocker covers.
       Doug Braun
       blue 73L #550
       -----Original Message-----
       From: DeTomaso [mailto:[2]detomaso-bounces at poca.com]On Behalf Of Tony
       DiGiovanna
       Sent: Sunday, March 08, 2015 4:00 PM
       To: [3]detomaso at poca.com
       Subject: [DeTomaso] Rocker Arms
       351C, solid flat tappet cam with lift of 0.640.  7/16 screwed-in
       studs.  Any
       opinions on Rock Arms? PRW vs. Harland Sharp vs. other?
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-------------- next part --------------
   i>>?

   Brian,



   I had a wrong dimension for the pushrods in my first email.  I meant to
   say that you have to be careful when you use 3/8" dia pushrods which
   are larger than the stock 5/16" pushrods.

   It's not the 7/16" studs that cause the rocker binding problem with
   high lift cams.  Most every roller rocker has plenty of rocker stud
   clearance for high lift cams.  But not all of them are properly
   clearanced for use with larger diameter pushrods when using high lift
   cams.  The side of a larger 3/8" diameter pushrod can bind against the
   backside of the rocker body at near full lift.



   Doug Braun

   blue 73L #5505

   -----Original Message-----
   From: Brian Dudley [mailto:bd8134 at gmail.com]
   Sent: Monday, March 09, 2015 12:28 PM
   To: doug351c at gmail.com
   Cc: mark skwarek; Tony DiGiovanna; detomaso
   Subject: Re: [DeTomaso] Rocker Arms

   As per George Pence's sticky..
   "If your motor's cylinder heads are milled and tapped for 7/16" stud &
   guide plate type rocker arms the Yella Terra YT-6321 rocker arm is the
   hot tip. This very rugged rocker arm also performs like a shaft mounted
   rocker arm therefore it requires no studs, guide plates or hardened
   push rods. Internet pricing for the Yella Terra YT-6321 rocker arm is
   in the range of $650 US dollars for a set of 16, sometimes even lower.
   That may look "pricey" up front when compared to the standard push-rod
   guided arm, but they don't require studs, guide plates, poly-locks or
   heat treated push-rods. Once you add up the price for a set of
   conventional roller rocker arms plus all the additional stuff you need
   the price difference is not that bad ... some guys feel it is
   break-even."
   I am using these with a solid cam with the same lift.
   Stock valve cover fits.
   Using a rocker that you have to modify sounds like it is designed for a
   lower lift.

   On Sun, Mar 8, 2015 at 10:49 PM, doug351c <[1]doug351c at gmail.com>
   wrote:

        i>>?
        Yep Mark - that can't be empahsized too much.  That's why I said
     the
        backside may need to be clearanced. (it bit me too !!!)
        Doug
        -----Original Message-----
        From: mark skwarek [mailto:[2]ehpantera at yahoo.com]
        Sent: Sunday, March 08, 2015 6:34 PM
        To: [3]doug351c at gmail.com; Tony DiGiovanna; [4]detomaso at poca.com
        Subject: Re: [DeTomaso] Rocker Arms
        Just make sure that you have clearance between the pushrod and
     the
        rocker base at full lift. Under high lift the pushrod can make
     contact
        with the base of the rocker arm. Them the end of the rocker arm
     end
        will break off. Been there, done that.
        Mark
        On Sunday, March 8, 2015 9:48 PM, doug351c
     <[5]doug351c at gmail.com> wrote:
        I like the Scorpion Endurance SCP3023 1.73:1 forged aluminum
     roller
        rockers.
        They have a hardened insert seat, the shaft is centerless ground,
     a
        7/16"
        poloc nut is included and they have a great lifetime warranty.
     $326 a
        set
        at Summit Racing.
        Max spring dia = 1.625"
        [1][6]http://www.summitracing.com/parts/scc-scp3023bl
        I'm running these on my 70 Cleveland Mach1 engine.  Please note
     though
        that
        if you intend to run 7/16" dia pushrods, their backsides need to
     be
        clearance for them.  Scorpion's Endurance series cost more than
     the
        Race
        series but they have a narrower body and shorter polylocks so
     they fit
        better under stock rocker covers.
        Doug Braun
        blue 73L #550
        -----Original Message-----
        From: DeTomaso [mailto:[2][7]detomaso-bounces at poca.com]On Behalf
     Of Tony
        DiGiovanna
        Sent: Sunday, March 08, 2015 4:00 PM
        To: [3][8]detomaso at poca.com
        Subject: [DeTomaso] Rocker Arms
        351C, solid flat tappet cam with lift of 0.640.  7/16 screwed-in
        studs.  Any
        opinions on Rock Arms? PRW vs. Harland Sharp vs. other?
        _______________________________________________
        Detomaso Forum Managed by POCA
        Posted emails must not exceed 1.5 Megabytes
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        3. file://localhost/tmp/tmpfWSGk7.html
        4. file://localhost/tmp/tmpfWSGk7.html
        5. file://localhost/tmp/tmpfWSGk7.html
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References

   1. mailto:doug351c at gmail.com
   2. mailto:ehpantera at yahoo.com
   3. mailto:doug351c at gmail.com
   4. mailto:detomaso at poca.com
   5. mailto:doug351c at gmail.com
   6. http://www.summitracing.com/parts/scc-scp3023bl
   7. mailto:detomaso-bounces at poca.com
   8. mailto:detomaso at poca.com
   9. mailto:DeTomaso at poca.com
  10. http://poca.com/mailman/listinfo/detomaso_poca.com
  11. mailto:DeTomaso at poca.com
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