scorpion roller rockers

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oklahoma
My Car
1973 mustang sportsroof - 351c 2v - fmx trans.
Hello folks, does anyone know if pedastal mount scorpion roller rockers will fit under stock cleveland 2v valve covers without to many modifications to the baffles?

Thank you

p.s. I saw a set of the old stock fms pedastal mount roller rockers that are still available for the cleveland, thoughts on those?

 
I have them on my '69 with a 351c. My valve covers are the aluminum boss 302 style. I had to modify the baffle around the fill cap and the PVC valve, otherwise they were ok. Not sure about the stock stamped covers though.

 
Hi Guys,

I have also used them on my 71 Cleveland 2V für the initial engine build after restoration. I removed them after a few days due to a geometry problem.

They are advertised to have the stock ratio of 1:1.73, but in fact the contact point of the pushrod is closer to the pivot than with the stamped steel originals - which are also specified 1:1.73.

There is no problem with valve lift, but on 4 of eight cylinders the pushrods scrape in the cylinder head openings. These need to be modified when you intend to use the Scorpions.

Secondly, the contact point on the valve stem is not ideal (too far to the engine center). So there is also work to be done.

Image 1:

Here you can see how critical clearance is.

DSC02675.JPG

Image 2:

Here is the normal configuration with the stock rockers.

DSC02677.JPG

 
Last edited by a moderator:
Hi Guys,

I have also used them on my 71 Cleveland 2V für the initial engine build after restoration. I removed them after a few days due to a geometry problem.

They are advertised to have the stock ratio of 1:1.73, but in fact the contact point of the pushrod is closer to the pivot than with the stamped steel originals - which are also specified 1:1.73.

There is no problem with valve lift, but on 4 of eight cylinders the pushrods scrape in the cylinder head openings. These need to be modified when you intend to use the Scorpions.

Secondly, the contact point on the valve stem is not ideal (too far to the engine center). So there is also work to be done.

Image 1:

Here you can see how critical clearance is.

Image 2:

Here is the normal configuration with the stock rockers.
Can someone tell me if pushrod guides are necessary with roller rockers? I thought that roller rockers are not self aligning so the are required along with hardened push rods.

Spechti, did you mill the heads and changed cam shaft lift? Are you using stock length push rods?

Sorry for diverging here just trying to learn some basics here whenever I see something that I need to learn about. Since this was mentioned I'd thought I'd ask.

thx

 
Hmmm, I will have to pull a cover and check that interference. I didn't notice it last time I was in there or during assembly, but you can't be too careful.

 
Spechti, did you mill the heads and changed cam shaft lift? Are you using stock length push rods?
Yes, the camshaft is a Crane Cams hydraulic roller cam with .56 lift. I use Crane vertical bar hydraulic roller retrofit lifters. This combo needs custom pushrods in a length from approx. 7.80 to 7.85 inch. In my case, the 7.80 were the recommendation from Crane, but they were noisy and had too much slack. So I used the Crane rods in 7.85 inch length and the valvetrain is quiet now.

The Scorpion rocker arms do not need guides, because they move only on one axis. They are also not adjustable. Adjustments only can be made by shims under the pedestal, head modification, valve tip modification or pushrod length.

The Scorpion rocker arms also fit under the stock Cleveland valve covers. This means you can set up a highly advanced valvetrain in an externally totally stock appearing engine.

 
Last edited by a moderator:
Spechti, did you mill the heads and changed cam shaft lift? Are you using stock length push rods?
Yes, the camshaft is a Crane Cams hydraulic roller cam with .56 lift. I use Crane vertical bar hydraulic roller retrofit lifters. This combo needs custom pushrods in a length from approx. 7.80 to 7.85 inch. In my case, the 7.80 were the recommendation from Crane, but they were noisy and had too much slack. So I used the Crane rods in 7.85 inch length and the valvetrain is quiet now.

The Scorpion rocker arms do not need guides, because they move only on one axis. They are also not adjustable. Adjustments only can be made by shims under the pedestal, head modification, valve tip modification or pushrod length.

The Scorpion rocker arms also fit under the stock Cleveland valve covers. This means you can set up a highly advanced valvetrain in an externally totally stock appearing engine.
Thx for the update Spechti.

I used Harland Sharp roller rockers and have guide plates to help with the geometry. I also had to go with shorter push rods because of the higher lift cam and the heads milled. Was just wondering why I didn't see guide plate on your install. Didn't realize that some applications didn't need them.

thx

 
Thanks for all the info folks, I am still on the fence on this one because my engine is running so good right now. I have an appointment with the alignment shop tuesday then I'll be ready to put some miles on this thing finally.

 
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