The Stovebolt Site Forums The Shop Area Engine Shop 261 valve springs

I'm gonna run my 848 head from the 235 on my new 261 motor. In the manual it gives different specs for the springs. Apparently the 261 got stronger spring with rotators. After reading this board for awhile I've yet to see any mention of this, despite seeing many people running 848's on their 261's. I'm gonna change mine, and do a 'lil port work while it's apart. Has any one else done this, or do you all just run the 235 springs with the 261 cam? Also the valves seem like they have stellite tips?

I don't have an 848 on my 261 but when changing a cam you should change the valve spring to the ones the cam supplier list for that cam.And make sure you have the proper length 261 push rods as a quality check.

I'm running the stock cam from the 261. My motor is complete, now. I had my 848 from my 235 milled and v/j'd, and it's installed on my 235 now. Headwork cost me around 450.00, so I wanna keep it for the 261. So, I guess the cam manufacturer ( Chevy) recommends the 261 springs.

Chevy used '261 valve springs' also in truck 235s with solid lifter cams starting in 1956 and PG car 235s with hydraulic cams starting in 1954.
848 heads always were supposed to use '261 valve springs'.

Correspondingly 261 cams were used in truck 235s with solid lifters starting in 1956.
And the hydraulic version of the 261 cam was used in PG car 235s starting in 1954.

Strange, I have the 1960 shop manual. it lists two different specs for both the cams and the springs. The 261 cam is listed as having higer lift, but less duration. Also, the 261 springs are said to have rotators on them. I will inspect them closely when it comes apart, as the 235 is a 1962, and my 261 is a 1960. Could it be that this info only applies prior to 1960?

Btw, my manual is truck specific.

blackjack62,

My Shop Manuals (56-62) list the same information as yours.

Maybe the later parts manuals simply listed one cam as a replacement cam for later truck/mechanical-lifter 235s and 261s?

Tim

The info I provided is from the master parts catalog.
I always found this to be a very accurate and great source of info.

The 1960 truck shop manual does show different springs between 235 and 261.
However, it also shows specs of the older steel forged 1941-53 solid lifter cam #251 for the 235.
Starting with 1954 PG and all 55 models had cast iron alloy cams, also described in the cam spec section of the same manual.
848 heads were introduced in 1954 with higher load springs.

My 1962 car 235 has the 1954-62 stock hydraulic cam #252, almost identical to the 261 cam lift and duration specs.
A good cam grind for a 235 above 2500 rpm.

Higher lift 235 and 261 motors should have higher load springs and the later pushrods if used above 2500 rpm and especially higher.
Not sure about valve rotators reliability at higher rpm. I don't use them on my engines.

Well, in another post I found a link to a Master parts catlog that only goes up to 1957. It lists the cam p/n 3836484 as fitting 53-54 corv, 54-55 util (6 cyl), and 54-up comm util ( w/ 261) only. It has a serperate p/n for all other 6 cyl.s. The site with the master catalog is chevy.oldcarmanualproject.com/1929_57chevyparts/57cmpc0138.html.
the relevant sections are 0.519.
the spring are listed as the same,starting in '56 I think, but they have a seperate p/n for corv. inner's. this is located @ 0.303.
I also noted that a 261 long block w/ 11" clutch sold for around $450.00 in 1957!! I'll take three please!

Here is a direct link to the page listing the camshafts.

http://chevy.oldcarmanualproject.com/1929_57chevyparts/57cmpc0142.htm





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Edit:
Just noticed my post count. - Ironic, just as I was talking about the 848 heads.
Maybe time to wrap this up. Been here for a long time.
Learned a lot in the beginning and posted all I have figured out over the years and would just keep repeating myself.
Redundancy in engineering is a good thing, but in information it takes up precious space and muddies the waters.
I never forget the early days and the insights I gained from all the knowledge out of reach before this great source came along.
Thanks John and Peggy!
I hope the vast archives will remain and keep enlightening and inspiring stovebolters keeping their sixes alive and ticking.
...see you on the road.
Chris

Hey, dont stop now! You have lotsa knoldge that is sorely needed. You, and the others on this site have inspired me and all who find you! Thanks for your help and please feel free to help some more!