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Discussion Starter #1
I have a 347" SBF with a busted roller rocker. The engine has < 5,000 miles over last 10 years. It has been running good. No sure if I over rev'd or what. Looking to replace the busted rocker I'm lost on the red, blue, etc colored rockers. Does the color mean anything? Mine are kind of a blue/green. I've not found any to match my odd blue/green color. I see Edelbrock has "red" single rockers for about $40. Any help would be much appreciated.
 

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I'm no builder but I thought color combo could be personal preference, it was the ratio in which made them unique... i.e. a 1.6 ratio could be purchased in blue, red, etc etc, same as a 1.5 ratio rocker.

Again, im no engine builder, but that has always been my take on it

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Color doesn't really mean anything. And they're anodized. So over time, the color will change.

Do the rockers have any markings on them? Most manufacturers will put their name or part number on the parts. If you can't identify the maker, it's probably a cheap offshore copy of a real performance part. I'd get rid of all of them and install a good name brand.

Also, what kind of spring pressure do you have? High spring pressure and aluminum parts may not be a good mix. I really like Comp Cams stainless steel rockers. They might be a little heavier, but not by much. They're smaller, spring retainer interference is not a big worry. And they are extremely durable.
 
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Discussion Starter #5
Color doesn't really mean anything. And they're anodized. So over time, the color will change.

Do the rockers have any markings on them? Most manufacturers will put their name or part number on the parts. If you can't identify the maker, it's probably a cheap offshore copy of a real performance part. I'd get rid of all of them and install a good name brand.

Also, what kind of spring pressure do you have? High spring pressure and aluminum parts may not be a good mix. I really like Comp Cams stainless steel rockers. They might be a little heavier, but not by much. They're smaller, spring retainer interference is not a big worry. And they are extremely durable.
 

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replace the whole set i wouldnt trust the rest of them remember these parts are for racing engines longevity is not required , i would be more concerned if you had piston to valve contact
 

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What Chris said... make sure there isn't something else that caused the rocker to brake. The pushrod has to be straight or it also needs to be replaced. Many things that can lead to this. You'll have to adjust the valve lash when installing the new rocker. You should also check all the other rockers and check / set the lash on them as well. Then make sure the timing is good before your done.
 

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Discussion Starter #8
The busted rocker was on #5. When I pulled the plugs for 5-8 I found #8 was black. Next step is to run a compression check and see what the engine health is like. I'll post again in a week or two. Thanks for the comments.
 

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After some effort I did get my new compression gauge hose connected to #8. The compression looks good. Due to limited space it is difficult to get the compression hose on #6-7 connected, but I'll continue to work on it.

This summer I changed the spark plugs, distributor cap and rotor (MSD). I had installed new plug wires earlier in the spring. Today I noticed soot on #8 is very heavy. #8 on the old plugs had soot on it but nothing like the new plug. The other plugs looked OK. I'm going to trace my plug wiring to make sure I don't have a connection problem.

As far as spring pressure and its impact on the aluminum rocker arms: I purchased a 87 Mustang for a donor car from a guy in a neighboring town that seemed legit. It had a built 347 that I used for my Cobra. According to the builder he did an "old school" build using 1972 351 Windsor heads shaved .040 with a lot of porting work. It ran very well. He disappeared shortly after I purchased the car so all I have is brief notes he made before his departure. I ended up over my build budget a never considered swapping the the heads.

I will never race my Cobra so I'll likely install more/less stock rocker arms. Price is an issue. Recommendations will be appreciated. I'll update the post as I get everything put back together.
 

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I have used these before. They're essentially a higher quality stock replacement. If your cam lift is below .600'ish, they should work fine on a 3/8" stud.


 

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Discussion Starter #11
I have used these before. They're essentially a higher quality stock replacement. If your cam lift is below .600'ish, they should work fine on a 3/8" stud.


The builder notes I referenced above note "the 351 Windsor heads were shaved something like .040 and machined and tapped for screw in 7/16 studs with fully roller rocker arms".

I verified this morning the studs do fit a 7/16 nut.
 

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The builder notes I referenced above note "the 351 Windsor heads were shaved something like .040 and machined and tapped for screw in 7/16 studs with fully roller rocker arms".

I verified this morning the studs do fit a 7/16 nut.
Easy and inexpensive solution. For $40, change the rocker studs. With a broken rocker, you might want to do that anyway.

 

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Discussion Starter #13
Easy and inexpensive solution. For $40, change the rocker studs. With a broken rocker, you might want to do that anyway.

The rocker stud is 7/16 all the way. The threads into the block are course while the stud above is fine thread. Would not the 3/8" stud be 3/8" on both ends?
 

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Nope. The stud base is 7/16"

Base Thread​
Part #DescriptionDia.LengthStud Dia.Effective Stud Length
4500-16High Energy™ Rocker Stud7/16”.680”3/8”1.750”
 

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Discussion Starter #15
Bob, thanks for staying with me on this. I'll order the new rocker studs and the steel rockers you recommended. Jim
 
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Glad I could help. :)
 
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