Topic: Rocker Arms for 289

[Schmalz1184]

Hello everyone,
I am new to this forum. I have a question that I have been trying to find the answer for awhile. I am in the process of finishing up the top end of my 66 289 engine for my 66 mustang. I would like to put the roller tip rocker arms on to add a little more power and less wear. My question is can I put these directly in place of my old rocker arms without and modifications/other parts etc? I have the small slotted pushrod holes in the heads that kept the old rocker arms aligned. I have a mild, flat tappet cam in also. Will this work with the roller tip rockers as a direct replacement with no mods? Thanks in advance for the help. Im sure someone knows the answer.

[ol dirty doug]

yes they have roller tip rockers thah are a direct bolt in, look at JEGS or SUMMIT i had some in my old 68 and gained some power by going to a different ratio. just do your homework if you change the ratio.  they have shaft or pedistal mount.

[Schmalz1184]

What is the difference in the shaft and pedestal mounts? I was going to get the 1.6 ratio, would this be close to stock?
Thanks for the help.

[Soaring]

The pedestal mount means that the rocker fulcrum bolts directly to the rocker pedestal. Modern GT-40, E7xx and most of the newer heads are like this. Easy install, just bolt then down and torque. Geometry is adjusted by shims under the fulcrum. 351C's are also stock like this.

Shaft mount rockers are just that - they are mounted on a special shaft and pivot on that. The shaft is the fulcrum. New stuff is very high end, cost big $$$. Except for older OEM stuff that came like that - the FE engines come to mind.  Shaft rockers are the  best,  but expensive.

Stud mount is pretty common, the rocker mounts on a stud screwed into the head. OEM types typically use a self guided rocker and positive stop stud, aftermarket and hotrodders use a stud with more thread to allow for adjustment and a guide plate to keep the rocker lined up with the valve.

The typical 289 is stud mount.  Here is a site to get you started on buying the rollers.
http://www.thefind.com/cars/info-cams-roller-tip-rocker-arm

[Boss351Dude]

One thing people forgot to mention is the clearance problem you may encounter depending on your valve cover choice. You need taller valve covers than stock for rollers.

[Schmalz1184]

I will need taller valve covers for just roller tip rockers? I thought they would be the same size except for the rollers on the end.
Thanks for the info.

[Soaring]

In some cases Hi-Tech or Pro Magnum Roller Rockers will not fit under stock valve covers due to the height of the polylock. Most aftermarket tall valve covers will not have any clearance problems. However, you should always check for interference.