V8 guys - let's talk about rocker arms, adjusters, shafts and pushrods

[Dwain G.]

Jack,
I'm getting some info together to send you.

[StudeRich]

Since Jack's string was originally REALLY about: Rocker Arms, Adjuster Screws, Rocker Shafts and Push Rods.

I think THE important thing to talk about is here Compatibility.

It is pretty obvious to me the change noted to the 1550613 Rocker Arm was in Mid 1961, that tells me that it very likely coincides with the small Oil holes change in the '61 to '64 Rocker Shafts.

Has anyone verified that and the matching Push Rod to use?

Some people MAY want to build their '55 to '60 V8 as OEM, but myself I only care about the LATEST and Greatest improvement setup, THAT is what I want to run, for the Max durability of 259 & 289 builds.

Most of My "rebuildable's" ARE Late '62 to '64 Type Full Flow Engines and as long as I don't mix any older Top end Parts which I have Lots of into the build I should be fine.

But I realize that others want to know the Correct combination of parts for each year's of the Changes. I guess a CHART of the Changed Years of each of the FOUR Parts would help?

[PackardV8]

Since Jack's string was originally REALLY about: Rocker Arms, Adjuster Screws, Rocker Shafts and Push Rods.

I think THE important thing to talk about is here Compatibility.

It is pretty obvious to me the change noted to the 1550613 Rocker Arm was in Mid 1961, that tells me that it very likely coincides with the small Oil holes change in the '61 to '64 Rocker Shafts.

Has anyone verified that and the matching Push Rod to use?

Some people MAY want to build their '55 to '60 V8 as OEM, but myself I only care about the LATEST and Greatest improvement setup, THAT is what I want to run, for the Max durability of 259 & 289 builds.

Most of My "rebuildable's" ARE Late '62 to '64 Type Full Flow Engines and as long as I don't mix any older Top end Parts which I have Lots of into the build I should be fine.

But I realize that others want to know the Correct combination of parts for each year's of the Changes. I guess a CHART of the Changed Years of each of the FOUR Parts would help?

For true, Rich, later is better, but it's common to find CASO Stude builds of a mix of whatever was handy. One has to know how to identify each part to insure they are a match and are the latest.

Dwain G said, "Jack, I'm getting some info together to send you."

Thank you, Dwain, for the very comprehensive collection of Service Letters pertaining to camshaft, rocker arm and pushrod design changes. When time permits, I'll update this thread.

[64Avanti]

The rocker arm shaft with the smaller oil feed hole went into production about mid 62 and most likely coincided with the full flow block. The last design for the rocker arm came out in 61 but there were two different screws used with that rocker arm. This was the rocker arm that had the oil fed to the top of the screw / socket. I have a table of all of the configurations for the rocker arms in the engine book I have been working on. I will post the table later this week.

[64Avanti]

Here is a table showing the rocker arm assemblies and the rocker arm and screw part numbers. The first rocker arm did undergo several changes in the first year or so. The first two rocker arms are almost identical except the pad that actuates the valve was made wider on the second one.

[64Avanti]

I forgot to say that I don't think the 1550621 assembly was listed in any of the parts books.

[StudeRich]

Very GOOD Info David, thank you very much!

My "C" Drive is getting really Full of these "Beyond the Shop Manual" and Parts Catalog Service and Parts Tips that are very helpful.

[64Avanti]

Well I have been working on a book about the V8 engine for a while and that is were I have that kind of information. It is about 100 pages right now.

[64Avanti]

The other thing I had intended to post was that the difference in pushrod length is due to the difference in the newer verses the older rocker arms. The newer arms starting in 1961, have the bottom side where the screw goes in, .15625" higher. regardless of the screw used the amount screwed in on the assembly initially is the same on all rocker arm assemblies. This places the pushrod socket .15625" higher on the newer assemblies and the nominal difference between the older and newer pushrods is also .15625"

So that is the story on the pushrod lengths. (Nominal length = 11.1953125" for older pushrods and 11.3515625" for newer ones)