Chevy Roller Rockers

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93ragtop

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OK this may be a dumb question, so go easy on me!!

I have a set of crane 1.6 roller rockers. These used to be on a motor I had....

But here is my question. What does it take to use the chevy rockers on a magnum motor?
If I can use them in the future, I will keep them.... Otherwise, might as well sell them.
Thanks for your advise!!
 
As I understand they can be used but geometry between rocker manufactures can vary as well as your heads. Your best bet is to mock them up and see, they may or may not workout.

When I built my 460, a lot of rocker MFG said a BBC rocker will work too, but many people found that wasn't the case as true BBF rockers were different geometry wise. Sometimes the BBC geometry would work in certain cases that were not stock.
 
For mock up and testing geometry you just need the studs for the magnum head, but check your rocker stud diameter before ordering, and checking pushrods. If mock up shows good geometry, get guide plates and hardened pushrods in the required length. That's basically it, if you already have the poly locks for those rocker arms.
 
The accepted way to use GM rockers on a mopar magnum is to drill and tap the stud holes in the heads to 3/8 and use screw in rocker studs instead of the magnum press in style.
With any spring pressures over stock there is a possibility of the press in's pulling out of the heads.
Also magnum studs are 5/16 and Chevys are 3/8 (probably the ones you have are for a 3/8 stud.)
But yea, using Chevy rockers on a magnum is common.
 
I never saw a factory 5.2 or 5.9 magnum head with press in studs. I do have a set of heads on a 360 magnum that I got used in the mid 90s that looked like it had pressed in studs, but upon closer inspection it turned out to be the Crane conversion studs that are threaded but do not have a hex, they use a jamb nut for installation. Look up Crane part number 36655-2. I think that is what it has and you can see them. Also, those Crane studs use plastic pushrod guides so hardened pushrods are not required.
 
TrailBeast said:
The accepted way to use GM rockers on a mopar magnum is to drill and tap the stud holes in the heads to 3/8 and use screw in rocker studs instead of the magnum press in style.
With any spring pressures over stock there is a possibility of the press in's pulling out of the heads.
Also magnum studs are 5/16 and Chevys are 3/8 (probably the ones you have are for a 3/8 stud.)
But yea, using Chevy rockers on a magnum is common.
Click to expand...

If the camshaft he's running doesn't require a lot of spring pressure, he doesn't have to drill and tap anything. He can run this kit:

Crane Rocker Arm Guideplate Conversion Kits 36655-16

It's nice. I have it on the 302 going in RobKat.
 
Bobzilla said:
I never saw a factory 5.2 or 5.9 magnum head with press in studs. I do have a set of heads on a 360 magnum that I got used in the mid 90s that looked like it had pressed in studs, but upon closer inspection it turned out to be the Crane conversion studs that are threaded but do not have a hex, they use a jamb nut for installation. Look up Crane part number 36655-2. I think that is what it has and you can see them. Also, those Crane studs use plastic pushrod guides so hardened pushrods are not required.
Click to expand...

I may have misunderstood what I saw about the pressed studs, and upon looking them up I only see threaded.
Apparently the deal is to tap and rethread for 3/8, and the ones I saw had the hex at the base but it was a shorter hex as to clear the rocker.
 
RustyRatRod said:
If the camshaft he's running doesn't require a lot of spring pressure, he doesn't have to drill and tap anything. He can run this kit:

Crane Rocker Arm Guideplate Conversion Kits 36655-16

It's nice. I have it on the 302 going in RobKat.
Click to expand...

True enough, and I am one of those.:D
I'm running the Hughes 1110 springs with the 5/16 stock Magnum studs, but I am guessing the OP's Chevy rockers take a 3/8 stud.
There is also a stud that has the Magnum threads in the head with a 3/8 upper section for running Chevy rockers without drilling and retapping the heads.
 
TrailBeast said:
True enough, and I am one of those.:D
I'm running the Hughes 1110 springs with the 5/16 stock Magnum studs, but I am guessing the OP's Chevy rockers take a 3/8 stud.
There is also a stud that has the Magnum threads in the head with a 3/8 upper section for running Chevy rockers without drilling and retapping the heads.
Click to expand...

Those ARE 3/8 studs. They are 5/16 on the head side and 3/8 on the rocker side.
 
Comp part number 4542-1 is the style for direct use with regular guide plates and GM rockers. I just bought a set but have not tried them yet.
 
RustyRatRod said:
Those ARE 3/8 studs. They are 5/16 on the head side and 3/8 on the rocker side.
Click to expand...

Ok, then I'm confused.
If they are already 3/8 then is it that some recommend drilling and retapping heads so it has 3/8 on both ends then?
 
TrailBeast said:
Ok, then I'm confused.
If they are already 3/8 then is it that some recommend drilling and retapping heads so it has 3/8 on both ends then?
Click to expand...

You don't understand. The Magnum heads have 5/16 holes. That's why a standard Chevy 3/8 stud won't work. The Crane kit has studs that are 5/16 on the head end and 3/8 on the rocker end. That allows you to use a rocker with a 3/8 stud on the 5/16 style head. Of course, like I said, you don't want to have a lot of spring pressure. I have the same cam in the RobKat motor that you have in yours. Nice and mild and easy on the valve train. As long as the OP isn't going wild, he can use that kit just fine.
 
RustyRatRod said:
You don't understand. The Magnum heads have 5/16 holes. That's why a standard Chevy 3/8 stud won't work. The Crane kit has studs that are 5/16 on the head end and 3/8 on the rocker end. That allows you to use a rocker with a 3/8 stud on the 5/16 style head. Of course, like I said, you don't want to have a lot of spring pressure. I have the same cam in the RobKat motor that you have in yours. Nice and mild and easy on the valve train. As long as the OP isn't going wild, he can use that kit just fine.
Click to expand...

Ah, got it as that was what I was thinking after I asked. :D
(a conversion part)
 
Comp Cams also has a set of studs as well as guide plates (but require hardened pushrods, no big deal) , bolt-on, no mods, for magnum style heads. 5/16" stud into head, and 3/8" rocker arm stud accepts dime-a-dozen Chevy sb style roller rockers.
 
Want to thank everyone for their input!!
But there is one other thing I need to mention.
The rockers I have are self aligning.
Does that change everything?
Oh, and the poly locks are 3/8 24 thread
 
What part number are they? If these are the self aligning style with little flanges on either side of the roller tip you will not likely have enough exposed valve stem tip to run those, but you can hold one in place without a stud to check that.
 
I used the standard Chevy roller rockers, with my Crane conversion kit on my 5.9 Magnum. No guided rockers ,were needed. However, I did need a lash cap ,and a custom length pushrod, for proper geometry. The Crane kit ,flat works ,keep the valve spring pressures relatively mild (300 -330 full lift).pressure wise @
500"-.530" full lift..
 
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I know this thread is about Chevy Rockers but what about useing ford Rockers? I found some one that has ford small block 1.72 Roller Rockers brand new I think for $100. They look like crane but haven’t asked the guy yet. I need a set for my 5.9 magnum build
 
well I think I got the adds mixed up that I Saw. They are 7/16 and are for clievand heads.
 
mopar65 said:
well I think I got the adds mixed up that I Saw. They are 7/16 and are for clievand heads.
Click to expand...

This may be splitting hairs, but the factory ratio for Cleveland rockers is 1.73, not 1.72. If the rocker is advertised for a Cleveland at 1.72, it is for a big block Chevy, as they are interchangeable. Most sellers advertise the 1.72 as fitting both. While they will, they are technically not correct for the Cleveland.
 
RustyRatRod said:
This may be splitting hairs, but the factory ratio for Cleveland rockers is 1.73, not 1.72. If the rocker is advertised for a Cleveland at 1.72, it is for a big block Chevy, as they are interchangeable. Most sellers advertise the 1.72 as fitting both. While they will, they are technically not correct for the Cleveland.
Click to expand...

Thanks for the info Rusty.
 
So what about the small block Ford Rockers. I did finally find the set I was talking about. Brand new for $100.

EE640650-331D-4F29-8656-C054A1FAAC92.png
 
if the self aligning rockers clear the spring retainers, then u do not need guideplates-if the valve stem diameter is close enough to the 11/32" chevy stem diameter
 
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