I mentioned in another post that I had a set of heads that were redone about a year ago that I intended to use. They are low comp heads so I have found another set that I may just go through completley with all new everthing. They are C80Z 4V heads. I understand that they are the smallest combustion chamber heads for those years and will give me around 10:1 compression with flat tops!.

Here is my question, I have seen rail rocker heads that have a little cap on the exhaust valves, and others that do not. The 68 heads do not have them and the other heads that I have which I believe are 77 heads do have them. What were they for? and are the 68 heads suppose to have them? Give me the rundown on the little caps and when and why did Ford use them?

The little caps are called lash caps . They were used on most small blocks 73-80 ish . Not sure why they made a shorter valve then created a lash cap to fix the problem .
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1966 Gt , Tahoe Turquoise , 35143 miles

After having some time yesterday to do a little research, I found that ford used the rail rockers from late 60's to some time in the late 70's. Thjey were put into play because the rail rockers were eating the top of the valves and causing the rocker to come into contact with the keepers and locks. The earlier ones on the 289's had shorter valve lengths and no lash caps. In 69 the 302's had a bit of a longer valve with a longer groove to tip length. These were the heads that had the Lash caps. So far I have only seen the lash caps on the exhaust valves.

They sell them in packages of 16 so that leads me to believe that they should be on all the valves.

So, the question is: When I rebuild my heads do I use them on both the intake and the exhaust. I'm using roller tiped rockers. Even though my heads are of the 68 design I am going to use the longer valves as that seems to be the fix! Does this seem right to you?

Talk with a machine shop before you buy any new parts. They will set you straight in regards to the question at hand. Most likely the new valves will not require the use of the lash caps. The metal used in them is a lot better then it was in the early 70's. Also the rollers will reduce a lot of the scuffing common to rail rockers.
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Mark J. Covill
"I'm not handicapped, I'm handicapable"