Nailhead Adjustable Rocker Arms

I am interested in buying a set of factory nailhead "adjustable
rocker arms". According to the "Buick Master Parts Book-1940
through 1970", two different sets were produced. Although most
people refer to them as "export", the Buick parts book call the
rockers "high power equipment".

The two sets are:

1. 1953 to 1956
2. 1957 to 1958

If anyone has a set to sell, or, would reply to me with the "casting
or part" number located on the top rib of the rocker, I would
appreciate it.

I am trying to determine the differences between the two sets. I
am aware that from 1953 to 1956 the engine size was 322, and
from 1957 to 1958 the engine size was 364. But why would the
rockers be different? Stock rockers for hydraulic lifters inter-
change from 1953 to 1958 (1.5 ratio), 1959 was 1.6 ratio (steel),
and 1960 to 1966 was 1.6 ratio (aluminum). All rocker shafts and
stands interchange from 1953 to 1966.

If I am able to acquire some "casting or part" numbers, I may be
able to sort out the differences between the two sets.

Thank you,

Marty

 

I just use Smith Brothers adjustable pushrods, www.pushrods.net

 

marty, go back on the archives, there are a few yah/nay stories on those rocker arms:Smarty: good luck, Frank

 

My interest in the "adjustable rockers arms" is that I have
collected some of Buick's oddities over the last few years.

Tom Telesco's "roller tip rockers" are definately the way to
go, and I am planning on purchasing those rockers as soon as
they are available.

If anyone can help me with info, or sell me a set of "adjustable
rockers", I would appreciate it.

Thank you for the replies,

Marty

 

"Export rockers"

Marty,

I have two styles of "Export" rockers. One style (I think early) has a bolt style adjuster that sticks through the rocker. It has a rounded tip that sits in a cup on the end of the pushrod. I think it has a tapered thread. I run this one on my car and they have not loosened up on me yet.

I also have another style (later?) which uses the more common style adjusters: an adjuster with a locking nut around it. THe adjuster is the cupped style and takes regular style push rods.

I hope this info helps.

 

Thank you Joe for your reply.

What you have described may be the differences
in the part numbers. It appears you have one
set of rockers on your car and an extra set.
Would you like to sell that set? Some former
Buick engineers suspected there may have a
ratio change from 1956 to 1957, but they were
just guessing. Is the pushrod side of the
rocker closer to the shaft from one set of
rockers to the others? I believe that is how
Buick changed the ratio from 1958 to 1959.

Are there any part or casting numbers that you
can see on the rockers?

Thanks again,

Marty

 

"export rockers"

Marty,

I am not ready to sell off the other set right now, I am planning on using them on my next engine and keeping this engine complete for a possible future project.:bglasses: :Brow:

Although I have not measured the distances, it appears that the "later" style is slightly closer to the folcrum(sp?) than the earier style. although it would be ever so slight a difference.

I could not see any casting numbers or part numbers but if I get a chance this week, I will try to get them in the parts cleaner for a better look.:TU:

 

Joe,

By moving the pushrod closer to the rocker shaft will
increase the rocker arm ratio. Buick changed the
ratio on the rockers on the "stock" engines in 1959
from 1.5 to 1.6. Perhaps they made this ratio change
earlier on the "adjustable rocker arms" in 1957.

Thanks again for the info,

Marty