My neighbor is putting a stroked 427 in a Studebaker pickup.Last night while adjusting the vale lash we noticed that the tips of the crane gold roller rockers are not centered on the intake valve stems.The heads are Merlin.Are the intake valves in a different location than a standard BBC? Is this common? What could be the problem? Thanks in advance for your help.

Your pushrods are not likely the right length.

Take the rockers off and using a felt tipped pen and color the valve stems, put the rockers back on and rotate the engine around a few times. Check the pattern location. It will be total carnage if the rocker tip goes off the valve stem while the motor is running.

Phil, Manley makes a pushrod length checking tool. It looks like a plastic rocker. with your incorrect length rods you can use the tool to determine exactly what the correct length is. OR get an adjustable pushrod and do it exactly the way Tom said.

Small block 427?

sounds like he might be talking about centered front to rear not inside to outside. Is this the case ?

Phil,
If you are talking about the rockers being off the sides of the valves (actually towards the front and rear of the engine) I have seen the problem several times on Merlin heads. I have had to cut guideplates in half and weld them back together in the correct position several times.

Bill,

Is there a way to tell this before hand or is it just something you will find out as you get to it?

Ah, sorry. Same with a pals Darts. He cut reweld guideplates. Someone makes a 2 pc guideplate for this, don't they?

Originally posted by 427L88:
Someone makes a 2 pc guideplate for this, don't they? Isky does...
http://www.flatlanderracing.com/guideplatesisky.html
But only for a SBC.
The big block guide plates you have to cut/weld like BillK suggested.

Originally posted by 427L88:
Phil, Manley makes a pushrod length checking tool. It looks like a plastic rocker. with your incorrect length rods you can use the tool to determine exactly what the correct length is. OR get an adjustable pushrod and do it exactly the way Tom said.

Small block 427? Just my opinion but I have found that little plastic tool to be about as useless as tits on a boar hog :D
I prefer to use checking pushrods.

Well, for a pro, sure. But for the average backyard guy who couldn't even see the contact patch well enough with fat tip roller rockers on there. I saw the disparity in installed heights ( have an 'outlyer' at -.050" ), and found that I needed pushrods about .025-.030" short. All in about 20 minutes. To wit, a good amatuer tool.

Brian and I went around about this as well. The $16 plastic tool is fine for a rough check IMHO, assuming the thing measures right.

Better than not checking, eh?

They may work with stock rockers, I don't really know, never checked but I tried one with two different sets of roller rockers a number of years ago and the length they showed was not even close.
Maybe I got a the only crappy one made, don't know all I know is it was way off. ;)
So,,, I don't recommend using them.

I haven't used the Manley plastic dealie, but Dave Vizard in his book on Small Block Camshafts and Valvetrains says it's "calibrated" for cams of around .600 lift. More or less lift requires "compensation". The Manley unit will produce a "too long" pushrod with more than .600 lift, and too short with less than .600 lift.