I am rebuilding a 1972 350 Olds engine and ran into an issue. I was checking for proper push rod length and notice the pattern on the valve tip was low (toward exhaust side). I tried to shorten the adjustable checker and the rocker itself bottomed out on the stud prior to acheiving the proper position on the valve stem. I am using Comp Cam roller tip rockers and hydraulic lifters, but the guide plates and studs are ones I purchased years ago for my 425 from Mondello. Any thoughts?

 

Try switching the rocker - gotta start somewhere!

 

You need a longer slot in the rocker. What's the lift on the cam?

 

are you using the actual springs on the valve or a light checking spring. if you use the real spring and a hydraulic lifter then the plunger will compress and it will look like you need a longer PR. when you figure the PR length you need to use a solid lifter or light checking springs on the valve so you get are working with the PR length when the engine is running.

 

you need to mill the rocker stud pads on the heads the thickness of the guide plate.

Gene

 

Is machining the stud pads a common practice when switching to adjustable rockers? The reason I ask is that I did not have to do this on my 425.
If you do have to machine the pads, is the thickness of the guide plate all you cut them down or do you need to measure the thickness of the stud base as well?
Additionally, will this machining require you to machine the stud mounting holes deeper?

 

If you machine for 7/16 studs and you have the thick guide plates, then yes you should machine.
Now if you are using the Comp cams roller tip rocker kit, I would say no, you need longer push rods.

Gene