The Stovebolt Site Forums The Shop Area Engine Shop 261 rocker arm order

Hi Guys,

I bought new rocker arm shafts for my '54 261, and wouldn't you know it, I got the arms out of order when cleaning them! :mad:

The casting number stamps are too faint to read, but there are large numbers cast into the arm. I have three each of #3,4,7 and 8. I've tried various combinations and what seems to line up best with the valves is the following order, front to back. (E=exhaust, I=intake)

3E,8I,4I,7E,3E,8I,4I,7E,3E,8I,4I,7E

But....according to the service manual (for the 235), #3 and 4 are supposed to both be intakes, and there is no mention of #7 or 8.

I thought that the 261 and 235 rocker arms were interchangable? What am I not getting here? :confused:

53Therapy,

This reply won't be of much help - more questions than answers.

1. What manual are you using? The 1954 Truck Shop Manual?

2. The 1954 (and maybe other years) rocker arms and shafts for the 261 were supposedly "beefier" than those on the 235 (this is stated in the 1954 Technical Specification Manual). The arms have different numbers on the 261 (1, 2, 5, 6) than on the 235 (9, 0, 3, 4).

3. The 1957 and 1960 Truck Shop Manuals show completely different numbers on the rocker arms. Most likely, the automobile 235 rocker arsm also have different numbers.

4. Nonetheless, most likely, all 1954-1962 235/261 rocker arm assemblies are interchangeable (in other words, they will fit on all the 1954-1962 235 and 261 engines). I would guess that they will all work OK for use on smaller trucks.

Regardless of the numbers on your arms, your Manual should show the orientation (and shape) of the rocker arms ("Fig. 15 - Layout of Rocker Arm and Shaft Parts" in my 1954 Manual). Also, the Manual shows the differences in body profiles for the Inlet and Exhaust arms (Fig. 14). Let me know if you want pictures posted (I could post them tomorrow).

Good luck,
Tim

If I remember correctly, the Shop manual is pretty specific. I think that you should have a left and right exhaust and a left and right intake, as types.

I have 3 rocker arm assemblies with 3 different numberings

Older 235: 9 0 3 4
Newer 235: 87 88 85 86
1961 261: 7 8 5 6

(The four code numbers are for 1-3-5 exhaust, 2-4-6 exhaust, 2-4-6 intake, 1-3-5 intake, respectively.)

Could it be that they mixed the 7 and 8 from a 261 with a 3 and 4 from an older 235? Is there a difference in their heftiness?

On every 235/261 I worked on, the rocker arm numbers shown in the factory manual weren't marked the stuff I was looking at.
They really only go on one way, so assemble them on the shaft without the stands and spacers so they match up properly to the valves. Then number them, and reassemble with all the parts.If it looks good,it is good.

I'm using the shop manual for the older trucks, up to '51. I should have invested in a '54 manual as well.

It sounds like this engine has mixed up 235 and 261 valves, but they both look equally "hefty".

Pictures would be a BIG help! Thanks!

Also, my intakes #3 & 8 have a "ridge" cast on each side of the arms, the exhaust do not, they are "plain".

Thanks