long stem valves and raising rocker shaft

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340 mopar

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My j heads have spring height of 1.70 and I want to go to 1.85 for a lunati cam, so I will use long stem valves. Can I shim the rocker shaft .150? If so, where can I get them?
thanks gary:thumblef:
 
I think that may be a problem Gary because the valves and rocker stands are not perpendicular. If you run valves that tall and shim the rocker stands your going to be moving the rocker arms and valves too far apart. Probably so far the rocker arm pad will no longer even reach the valve. Why not get the spring pockets cut and use spring retainers that give extra installed height? I had my heads cut for an install height of 1.8" and could have used retainers that gave an extra .050" inst. height but I didn't need it for my springs but I'd think that'd work for you.
 
You can get retainers that will allow .100 more installed hieght, but the rockers hitting the springs may be a problem. I don't believe setting the spring heights on the springs to1.7 would be any type of issue tho. What cam/spring requires 1.850?
 
Thanks guys, I talked to a cylinder head shop and they were scared to mill spring pocket without sonic testing or someone tell them they could go that deep. They said to use long stem valves which is also what my mopar engine book (8th ed) says to do. Book says to use stock TA rockers, but move shaft. Also says to mill off stands and install new brackets. I was hoping there was an easier way as I have never seen this done.
Cam is a lunati solid roller 60433
Thanks again Gary:notworth:
 
Wait.

With a .060 pop up retainer and +.100 chevy app valves I can get about 1.85/6 without milling stands, the the valve tip is right at the edge of being too low in relation to the retainer with it being cut to the 1.915 [spot on geometry]..though it's good and would work.

the other way you could get the height but maybe not have perfect geometry is to run a pop up super lock on a comp '741' retainer.

Im pretty damn sure you can cut .030 out of the spring pockets/seats, after that Im not so sure.
 
For a roller, anticipating high rpms, I would just mill the stands and run the rocker shaft blocks.
 
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