Author Topic: Roller rockers on stock rocker studs?  (Read 389 times)

SP Steve

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Roller rockers on stock rocker studs?
« on: February 10, 2018, 07:19:23 AM »
In this day of low zinc oil I'm thinking about putting a set of roller rockers on the 400 in my 71 Formula.  The motor has 96 heads and I think factory screw in studs????  Will a set of roller rockers fit on these studs or do I need to replace them with longer ARP studs?

phil400

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Re: Roller rockers on stock rocker studs?
« Reply #1 on: February 10, 2018, 07:51:32 AM »
Yes you need arp studs. But really the low zinc will not affect the rockers, it's more high lift performance cams the zInc levels affect.
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oldskool

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Re: Roller rockers on stock rocker studs?
« Reply #2 on: February 10, 2018, 09:45:06 AM »
Most rockers will work on bottleneck studs, since the rocker rides on the lower 7/16" portion of the stud. But you'll have to use 3/8" poly-locks.

Since there are cheap 7/16 studs available, there is no reason not to go with them. The higher priced ARP studs are not needed. Not many street Pontiacs run a spring/cam/rocker combo that will break one of the cheaper 7/16 studs. 

I think stock studs are aprox 1.75". There are lots of cheap studs in this length.

Here are some.

http://www.jegs.com/i/JEGS-Performance-Products/555/20582/10002/-1

https://www.summitracing.com/parts/sum-g1676/overview/

https://www.ebay.com/itm/New-Set-7-16-Screw-In-Rocker-Arm-Studs-1-765-Height-Small-Big-Block-Chevy/221600134027?epid=1930444560&hash=item339865b38b:g:hEQAAOSw9GhYdglY:sc:USPSPriority!71251!US!-1&vxp=mtr

https://www.summitracing.com/parts/mil-84287/overview/

There are longer studs. But, the stock length studs will probably work with most rockers. If you run longer studs, you may need taller valve covers. Many have posted that they were able to use stock valve covers, with the 5/16" thick gaskets, when using the stock length studs & roller rockers.

« Last Edit: February 10, 2018, 09:53:34 AM by oldskool »

79T/Aman

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Re: Roller rockers on stock rocker studs?
« Reply #3 on: February 10, 2018, 12:29:27 PM »
as oldskool said no need for ARP studs, inexpensive BBC 7/16" studs are fine just grid the tip flat before putting them in to give the poly lock set screw a nice surface to set.

If I were you I would look at installing 1.6 rockers at this time as well if the cam is stock, there should be no clearance problem with the push rod but you would not want to use the bottle neck studs with a higher rocker ratio, and don't go over 1.6 ratio.
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Bluebandit

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Re: Roller rockers on stock rocker studs?
« Reply #4 on: February 10, 2018, 02:06:23 PM »
To add to this, if you do decide to replace the studs, remove one and replace it then do the next and so on. That way the one that is tight will help keep the pushrod guide plate aligned while you replace the other one.

Re: Roller rockers on stock rocker studs?
« Reply #4 on: February 10, 2018, 02:06:23 PM »

rkellerjr

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Re: Roller rockers on stock rocker studs?
« Reply #5 on: February 10, 2018, 10:29:50 PM »
I did just what your asking about with my 400. Stock valve train w/roller tip rockers and I'm using the XE262H competition cam.


phil400

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Re: Roller rockers on stock rocker studs?
« Reply #6 on: February 11, 2018, 08:36:20 AM »
I guess things have changed years ago when I made the switch to cc roller tip rockers everyone told I had run straight 7/16, that it was not a good idea to run the stock bottlenecks. I stand corrected. The sumnit ones are fine, I meant to say 7/16, not necessarily arp's.
78 T/A 4 speed, Marty Blue, original paint, match #s mine since ‘99, 3rd & final owner as long as I'm alive.
https://www.youtube.com/watch?v=CbM_iVhwVQc
https://www.youtube.com/watch?v=AgqYOsWTJsE
98 Ford Ranger flare side 2.5L 5speed "old reliable" 187k and still going
77 T/A sold
85 Monte Carlo SS sold
83 Mustang GT sold
“Let me tell you what Melba toast is packing”

rkellerjr

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Re: Roller rockers on stock rocker studs?
« Reply #7 on: February 11, 2018, 08:53:58 AM »
I should also say that OLDSKOOL is right, you need poly-locks. In the picture you'll notice we initially used the original nuts torqued to 20lbs (I believe is the spec) with the intention to put poly-locks on it later. Bent a rod because the nuts worked lose.

79T/Aman

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Re: Roller rockers on stock rocker studs?
« Reply #8 on: February 12, 2018, 04:33:02 PM »
I should also say that OLDSKOOL is right, you need poly-locks. In the picture you'll notice we initially used the original nuts torqued to 20lbs (I believe is the spec) with the intention to put poly-locks on it later. Bent a rod because the nuts worked lose.

On a Pontiac you can't us the stock nut and torque if you use an aftermarket cam, the base circle is smaller so the lifter sits lower in the bore (this is why you should not use Chevy lifters in a Pontiac) but the nut bottoms out on the stud leaving too little pre-load on the lifter and push rod.
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Bluebandit

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Re: Roller rockers on stock rocker studs?
« Reply #9 on: February 12, 2018, 06:06:07 PM »
I originally ran stock bottleneck studs with 3/8" poly locks with aftermarket spring at around 115 lbs seat pressure. Lugged the engine down and broke a stud at the bottleneck. Replaced it and several weeks the same thing happened, same situation, lugged it down and broke another. Went and replaced the stock studs with 7/16" ones and never broke another. As I was removing the stock studs I found 2 more that were broken inside the poly lock but hadn't totally failed.

cyber104

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Re: Roller rockers on stock rocker studs?
« Reply #10 on: February 13, 2018, 06:18:54 AM »
I don't know about roller rockers on the original Pontiac studs - they should work - as long as they land on the shoulder of the stud like Oldskool said..  I can tell you that if you switch to BBC studs it will work since they are the same diameter top to bottom.

I just finished setting up my valve train also.  I'm using a mild Lunati cam.  I used stock bottleneck rockers and BBC studs and locking nuts.  One point that I need to stress since it caused me MUCH grief is the following:

If you are going to use BBC studs and locking nuts - Try to find a set of originals or buy the OEM from GM.  Also buy the OEM lock nut from GM.

I found that the BBC studs that I bought from a reputable engine builder were actually a bit smaller in diameter - they would have worked fine with poly locks - but even the OEM lock nuts threaded on VERY easy and certainly would have backed off.

Once I went with GM OEM everything (studs and lock nuts) it required SIGNIFICANT effort to screw those nuts down - just like it should.

In addition - I'm fairly sure that my poly locks (had I used them) would have worked with the OEM BBC studs.

Hope this helps.
« Last Edit: February 13, 2018, 06:45:00 AM by cyber104 »

SP Steve

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Re: Roller rockers on stock rocker studs?
« Reply #11 on: February 13, 2018, 06:27:15 PM »
Wow!  Thanks for all the info, guys!  I'll probably get a set of the extruded aluminum rockers like the Harland Sharps or similar, 7/16 studs and use valve cover spacers.  I'm thinking I may want to put a Comp Cams Thumper hyd roller cam in the motor down the road.

Re: Roller rockers on stock rocker studs?
« Reply #11 on: February 13, 2018, 06:27:15 PM »
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