NTChrist

Hi,
I've got a pair of 416 heads that are about to come back from the machine shop after being cleaned and magnafluxed.
If I'm correct, these heads should be pre-self aligning rockers, right?
I believe they made the switch to SA rockers when the intake bolt hole angles changed to the newer style(or somewhere in that vicinity).
These heads came with no guideplates or rockers (self-aligning, or otherwise), so I'm unable to tell what type of valve-directing they used on the last application.
Looking at pictures of guildplates (what I'm guessing came stock), I can't figure out a way for them to be secured to the head without the use of screw in studs. Am I missing something?
What am I supposed to use to secure the valve? Self-aligning rockers, or guideplates? What came stock on the heads.
I've tried a search, but was supplied with no answers.
Feel free to post as much info as you're willing to spew.
Thanks!

ede

you need screw in studs for guide plates

NTChrist

So the heads came stock with self-aligning rocker arms, I'm guessing?

Thanks for responding, ede.

Guest

Take a look at the pushrod hole.

NTChrist

I don't need EITHER guidplates, OR self-aligning rockers?!?!
That's music to my ears.
I'll buy a set of hardened pushrods, thanks!

five7kid

iTrader: (14)

You don't even need hardened pushrods. They are recommended for use with guideplates. Won't hurt anything to use them, though.

If you're using 1.6:1 rockers, you may need to elongate the pushrod holes a little. There's a tool avaiable to do that.

NTChrist

I have a LT1 roller cam, and a set of 1.6 stamped steel rockers waiting to go on the heads. This will take me to about 0.480" lift, so I will check for binding with the pushrod holes when the heads are on the car.

Anybody have any idea what an acceptable clearance between the pushrod, and the pushrod holes are?

Thanks for the info, five7kid.

RB83L69

Push rod hole clearance is not teribly critical, it's usually around .015". With 1.6 rockers you risk having the push rod bind at the of the hole end closer to the stud. It's impossible to guess whether it will happen to your engine or not; about half of all heads I've put 1.6 rockers onto had interference on at least one hole; and sometimes all the holes on one head of a motor interfered, and all the holes on the other head on the same engine were OK. I don't even bother with checking them any more; if the heads are off, I just go ahead and deal with it before I assemble the motor, it's less trouble in the long run. You either need to elongate the hole, you can get a "Louis tool" from Comp for doing that; or hog them out and change to guide plates. I usually do the latter. Although, those weak stamped sheet metal rockers will probably protect the rest of your valve train from any stress, by flexing and otherwise failing like they always do.

NTChrist

LOL

Yeah, I picked stamped steel because they can be bought for $66, out of Summit's catalogue, versus the $150+ for full roller 1.6 rockers.
I'll look into the tool from Comp Cams, thanks everybody for your help!

iroc22

88-up rockers were self-aligning.