455 valve train geometry and related questions

Old June 1st, 2018, 08:00 PM
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455 valve train geometry and related questions

Here is my problem. I have a pair of "E" heads with new valves and a fresh valve job. I wanted 1.7 ratio rockers so I purchased Comp 4542 studs and PRW Ford 351 self-aligning roller rockers. No guide plates. I have since read in the Comp catalog that guides are required so I will need to get some washers.

I am at this point mocking up the parts on the head before I put them on the short block. I have installed one set of original Olds rockers, 1 set of original Ford 351 rockers and one set of the PRW rockers. Laying a straight edge across the rocker mounting pad and the valve cover rail I stuck a pushrod up through the head until I had zero lash and marked the pushrod then did it for the factory ford rockers and found I would need pushrods approximately .2+" longer. I then checked the PRW rockers and found that it appeared I would need pushrods around .2" longer.

Will those who run ford rockers let me know if they found that they needed longer pushrods? Or do I have some other issue.

My next issue is that when the PRW nose roller is adjusted to what appears to be near the center of the valve, the lock nut is only engaging the stud threads about 1/4". I measured the depth of the nut, 1", and the depth to the stud when installed, .74", to get the engagement figure. If I install the equivalent thickness of the guide plate I would have around 3/8" of thread and that still doesn't seem to be enough to me.

Has anyone experienced a similar situation? Do I need to get the longer 1.75" studs?
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Old June 1st, 2018, 09:02 PM
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You are venturing into "custom land" which means when you try to change one thing, it seems like three other things have to be changed to work with that one.

This is one of those "it is what it is" situations, you need the longer studs to have plenty of engagement room for the adjusting nut (to keep it from breaking off the top of the stud, flexing the stud, or bearing down too hard on the locking grub screw, and you will need the longer pushrods to keep the valvetrain geometry correct, especially because of the increased ratio. Also, get rid of the small base diameter rocker studs, those like to break and flex a bunch when you push on them with tougher valvesprings and higher ratio rockers.

Look at Smith Brothers pushrods or Comp cams magnum or Hi-tech line of pushrods. Also, make sure you have a large enough and strong enough pushrod to match up to your valvespring tension. Small pushrods bend like spaghetti on the spintron when they are asked to push against very strong valvesprings.....

Last edited by Battenrunner; June 1st, 2018 at 09:06 PM.
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Old June 2nd, 2018, 06:07 AM
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this is what I used for my GA heads...
every situation is different, it is why you need a pushrod checking tool to verify what length pushrods are required

I required pushrods 9.950" long, they need to be hardened ones for use with guide plates
I got the pushrods from cutlassefi - Mark Remmel

https://www.summitracing.com/parts/cca-4542-16

https://www.summitracing.com/parts/cca-4842-8

https://www.summitracing.com/parts/cca-7706-1

https://www.summitracing.com/parts/lun-15385-16
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Last edited by naphtali5725; June 2nd, 2018 at 06:19 AM.
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