The Stovebolt Site Forums The Shop Area Engine Shop Years that 235 rocker assemblies will fit

Hi-

I was wondering if there is any difference in the rocker arm assemblies from 1954 -> 1962 other than the oil dump (the pinched pipe) I thought the only thing that was different in the heads was how the valve cover was attached.

Mine are worn and I'm looking to replace them. I have a 54 engine with a 55 and up head, or at least I think the heads are the same 55->62 ??

Is my thinking correct??

Thanks,

Brent

Brent, I have two heads here. Casting number 3835913(1954 to 56ish?) and the "higher" compression 3836848(1957-62). FWIW, After a careful look, I see no difference in the rocker rack, other than the oil dump you mentioned.

There are at least two different part number sets for the rockers. The rockers on my 848 head are different numbers than some earlier heads. Arms are shaped a little bit different, iirc. But they are interchangeable.

There were subtle differences through the years but the main difference took place in 1959 when the groove inside the rocker was moved 1/4" off center so it did not line up with the supply hole in the shaft. That and the pinched off supply tube pressurized the oil supply in the shaft.

They changed the way the oil gets up to the rockers I think it was 1958.

On earlyer engines you have a pipe going thru the side cover. Later engines used different lifters (with an anulus)and the oil comes up via a passage in te block.

If you have a later engine and head, the rockers are different. They have a offset oil groove at the bushing in opposit to a centered one on the earlyer models.

If you use the older rockers (with the centered groove or anulus)they flow much more oil and you get a big oil mess out of the valve cover.

SO...

if you use a post 58 block and head with anulus lifters an the oil line in the side cover you need the offset anulus rockers. Also you don`t want to have the overflow pipe between the rockers.

if you use a pre 58 block and head with the oil line and the straight tall tulip style lifters, you need rockerarms with the centered oil groove and a overflow pipe between the shafts

if you got a -lets say- 59 block and a 55 head GM service shops used a hollow head bolt for this combination - and it is getting a bit complicated.

hope that helps, Frank

Thanks for all the input, So I guess they are different. So the next question is if your rocker shaft and arms are not worn at the pivot. Is it common to have the rocker tips ground? If the rockers weren't so darn expensive the prefered method is to replace them. BUT.... not the case anymore.

Thanks,

Brent

With mechanical lifters, you need to grind the rocker tips every time the rockers are off the head, if the are showing signs of wear. What happens is the tips get dented from the valve, and then you can't accurately adjust the valves.