Isky ductile iron rockers

[Mpdave391]

I have a couple sets of the Isky ductile iron rockers
I put a set on my 440 so I can measure for pushrods but they don’t line up right on the top of the valve. Am I missing something or do I have to modify the hold down.

 

[pnora]

What heads?

 

[lewtot184]

Isky rockers were designed for the pre 64 head. Heads with cast in rocker stands will need some attention.

 

[Mpdave391]

Idk
I can pull the part number but they are stock cast iron heads to my knowledge anyways

 

[RemCharger]

Interesting. So I took a look at some iskys I have here, low and behold, the hold downs are indeed ground to fit.

 

[Mpdave391]

I was wandering if that was the case

 

[khryslerkid]

These are Cranes but I "modified" the hold downs and also used spacers, washers and shims. I don't remember the clearance needed anymore between each set.

 

[68jim]

I only recall having to grind down the two tabs on the larger spacers but that was quite some time ago...

 

[Dutchrebuild]

They make various size shims to push the rockers over...takes time and patience

 

[BSB67]

You need to grind the hold down tabs off. The lower portion of the rocker body may contact the cast pedestals. Use a thin shim between the rocker and pedestal and hold down. It will be close enough then.

 

[PRHeads]

I modified the rockers.
Machined them down to be the same width as the Cranes.

Either way will get the job done.

 

[Mpdave391]

Heads are 516 casting or at least it looks like 516

 

[72redbird]

You have to grind that little nub off the shaft hold downs. That will allow that rocker arm to move over more.

 

[wagonman]

The Iskys I had were shimmed and the springs were not used. Also the rockers had a hardened pad at the tip and were wider than those or Cranes. I also used 440 Source hold downs. Old school with a solid cam good to 7500 and bullet proof.

 

[1 Wild R/T]

I've machined quite a few sets of Isky's I intentionally cut them slightly narrow so I can use a shim between the rocker & the rocker stand... I made a simple jib for my lathe so I can knock out a full set in fifteen minutes....

 

[Geoff 2]

Lets clear up some of the BS. The valve spacing & rocker stand spacing was the same for all production heads from 1958 onwards. The width of the early alum block style shaft hold downs is the same as the later pressed steel hold downs.
The listing in the Isky catalogue says their ductile rockers fit all B/RB heads.

 

[Geoff 2]

The rockers in post #1 look nothing like the rockers in my Isky Catalogue. Did they change the design?

 

[RemCharger]

I only recall having to grind down the two tabs on the larger spacers but that was quite some time ago...

Maybe you're thinking about the 2 outer tabs that don't have to be ground off.

 

[1 Wild R/T]

The rockers in post #1 look nothing like the rockers in my Isky Catalogue. Did they change the design?

There were three versions.. Early had round hardened wear pads, second version had wide wear pads both of those look similar to what is posted above (the ones above are version 2) & the third version which is probably what your catalog shows came out around the early 90's looks like it's a reboxed Crane rocker except it has Isky cast into the body... In fact the ones Krysler Kid posted are Cranes..

 

[1968rt]

I have a couple sets of the Isky ductile iron rockers
I put a set on my 440 so I can measure for pushrods but they don’t line up right on the top of the valve. Am I missing something or do I have to modify the hold down.

Factory hold downs are a bit crude. I used aftermarket ones then filed them for better alignment