converting to roller rockers on C8VE heads

I'm switching from rail rockers to roller rockers on my C8VE heads on my 460.  This 460 powers my restored 1977 ford F150 shortbox with C6 4x4.   I'm running a comp cam extreme 4x4 cam.  Jerry's Custom Engines just machined the heads and replaced the original valve springs with taller ones recommended by comp cam. I'm planning on using guide plates and switching out to 7/16 ARP studs.

Do I need to machine the the rocker stud boss's?  I've read many forum posts where experienced builders claim that you absolutely have to machine at least the thickness of the guide plate off the boss.  Yet, others claim that if you select a rocker that fits on the stud so it can be tightened without running out of stud threads and the geometry on the pushrods work, than you don't need to machine.  For example, someone posted that a Harland Sharp S4073 should work with guide plates and no machining. But these those S4073 cost $440, is there a less expensive alternative?  Also, if you add  taller springs this should help counter the height of the guide plates? Would some scorpion roller rocker with 1.73 ratio work?

Does anyone have a configuration of roller rockerarms and guideplates that will work without machining? I want to run 3/8 hardened pushrods, but will not order until I get this figured out so I can measure the pushrods. I've also read that the guideplates sometime need to be cut and rewelded to deal with this issue.  Any advise or rocker arm suggestion would be appreciated.

Rocker Arm Guideplate Conversion Kit
1972-97 Ford 370-429-460 V8
7/16" Stud
3/8" Pushrod
Set of 16
Part #: 271-35655-16
$157.20

EDIT: These will not work for your c8 heads as they came with rail type rockers sorry brain not working yet ....

I believe the above mentioned kit is for the "pedestal" style heads, so might not work with c8,c9 d0 heads. When I switched my d0ve-c heads to adjustable rockers, I had the machine work done and was happy with the results. They used boss 302 or 351 cleveland rocker studs if I remember correctly.

Factory guide plates ( I have a spare set if you need them) and a 7/16ths stud. "Technicaly" the stud boss could be machined the thickness of the guide plate but in most cases it's not needed. The head is already drilled and tapped for them . Hardened pushrods are a must.

quote from 67hallet:

"In the 80+ years of 460 experience between me and my two biz partners, we have never had to mill the D0VE stud bosses further down in order to compensate for the addtion of guideplates when installing a roller rocker valve train. Whether or not that modification is really necessary is more of a clearance issue and has no effect on geometry, etc. Someone may find the modification necessary with certain rocker arm brands combined with OEM valve spring installed height, etc. I doubt that you will have this clearance issue since your camshaft probably uses a valve spring that calls out a greater installed height (1.900") than the OEM valve spring height (1.820).* If my assumption about your installed hight is correct and you are not using a Harland-Sharp roller rocker, then you ought to clear fine.

Quote Originally Posted by 67hallett View Post
Or can a guy just bolt on guide plates with bbc studs on dove heads and it will work with out longer push rods.
Whether or not the D0VE head's guide bosses have been milled has nothing to do with proper pushrod length or correct valve train geometry; it is simply a clearance issue. Meaning, if you can establish proper geometery (and thereby correct pushrod length) without experiencing clearance issues at the bottom of the rocker body's trunnion radius, then you're fine (you have good geometry and good clearance).

Oh, by the way, Ford 460's usually need a 1.900" BBF rocker arm stud, not the BBC 1.750" which almost always proves to be too short in the Ford engine. And so another nice thing about not milling down the guide bosses 0.100" unless necessary is that you have, in effect, "lengthened" that BBC stud by 0.100" and now it just might be long enough to use (depending on parts combination)....but I always go to the 1.900" studs.

* Please note that for several reasons, you cannot use your current 0.564" lift cam with the D0VE head's OEM valve springs. If it is your intention to transfer only your roller rockers/pushrods/studs/guideplates from the grenaded engine onto a BONE STOCK 1970 429 CAM & SPRINGS, then proper setup may require some changes but I can post a recommendation if you are doing this...I'll need to know your rocker arm brand, current pushrod length(s), and installed valve spring height of the grenaded engine. Setup won't likely be perfect from over the internet but ought to be plenty adequate for your budget-minded approach in this stock-build application."

GT350hr,

Is there a difference between factory guide plates and aftermarket guide plates such as manley, comp cam, etc?

If so, yes I'd like to purchase those guide plates.

Thanks,

Grizzlyo

Any suggestions on roller rocker arms?

Harland Sharps
Crane
Crower
Comp Cam
Scorpion

Which one gives me the most clearance?

Some people suggest the 1.75 CBB studs, because of the guideplates ... others say 1.9BBF.

Adding taller springs with the same lenght valves will not change were the tip of the valve is located.

grizzlyo wrote:GT350hr,

Is there a difference between factory guide plates and aftermarket guide plates such as manley, comp cam, etc?

If so, yes I'd like to purchase those guide plates.

Thanks,

Grizzlyo

   The factory guide plates are almost flat and have the Ford part number and logo on them. Aftermarket guide plates are often "stepped" to raise the "guide" portion closer to the rocker. If  $50 is good send me you address in a PM and we'll work out the details. I am in So Cal if it matters.

grizzlyo wrote:quote from 67hallet:

"In the 80+ years of 460 experience between me and my two biz partners, we have never had to mill the D0VE stud bosses further down in order to compensate for the addtion of guideplates when installing a roller rocker valve train. Whether or not that modification is really necessary is more of a clearance issue and has no effect on geometry, etc.

That broad faced quoted statement of 'has no effect on geometry" is totally untrue ... geometry IS affected.  Without milling the pedestals the pushrod tip will be further inboard to the cylinder when guidplates are used.  

Whether or not it has any ADVERSE affects upon valve tip, rocker arm or guide wear is something different altogether.

Randy,
You might want to rethink that. If the pushrod length and the valve stem height remain the same , the only thing affected is the proximity of the rocker to the hex portion of the stud. Certainly if the pushrod was lengthened or shortened , it would change the contact on the valve.
Respectfully,
The other Randy

+1

gt350hr wrote:    Randy,
        You might want to rethink that. If the pushrod length and the valve stem height remain the same , the only thing affected is the proximity of the rocker to the hex portion of the stud. Certainly if the pushrod was lengthened or shortened , it would change the contact on the valve.
   Respectfully,
      The other Randy

If the guide-plate is higher from the lifter, it contacts the pushrod higher and being that the pushrod is on angle, (if the guide-plate slots are not also moved slightly outward), that higher contact point WILL change the angle of that pushrod to slightly straighter and therefore the tip is now in a different location.
Not very much ... but, different.
The lengths and angles of the sides of a triangle is what geometry is all about.

Making that pushrod longer or shorter would change the tip location, also.
You can use one against the other and get the tip in the same as original lateral location if the pushrod is longer but, not with the same length pushrod.

Randy,
Yes you are correct. I'm sorry , I wasn't thinking in terms of the cant. I just drew it up on cad and it "could" move the rocker sideways as much as .005 (more if it were a "stepped" plate like Manley offers). Then I looked at the "slop" in the guide plate to pushrod and didn't worry any longer. LOL The same would hold true for changing pushrod length. The rocker would move a bit side to side .
RG

gt350hr wrote:    Randy,
        Yes you are correct. I'm sorry , I wasn't thinking in terms of the cant. I just drew it up on cad and it "could" move the rocker sideways as much as .005 (more if it were a "stepped" plate like Manley offers). Then I looked at the "slop" in the guide plate to pushrod and didn't worry any longer. LOL  The same would hold true for changing pushrod length. The rocker would move a bit side to side .
  RG

Yep ... you got it.
That is why I mentioned "ADVERSE affects" not meaning the same as actual tip location changes.  It is done all the time with no adversity but, it does make things slightly different.