Valvetrain Q's
 

I have comp 918 springs. I have all supporting mods and mildly built bottom end. My question is what would be better 7* locks and retainers or 10* locks and retainers?

10 degree

What is the difference? Why are the 10's better than the 7's?

Nobody can offer any insight?

Each valve lock is shaped like this \_/.

Wider angle (10°) locks better distribute the ever increasing valve spring loads over the retainer than typical 7° locks, reducing the chance of “pull-through” failure.

I look at the advantages of the 10 deg locks as:
1. They will come apart easier when/if you need to disassemble or make a change on a high load spring setup.
2. The installed spring height will remain more consistent, will not relax, as the relative motion occurs between the retainer and lock to achieve the clamping force on the valvestem (10 deg lock moves less than 7 deg does to achieve this clamp load).
Contrary to what many perceive, "pullthrough failure" is not the concern with 7 deg locks, unless you're referring to excessive relaxation of the installed height (no. 2 above) as failure. The small interlocking feature between the lock and valvestem is not what takes the spring load; that feature is only to locate the lock at the correct height on the valvestem during assembly. Of course it will also keep things located if your valvetrain is not up to par and it becomes unloaded during operation, ie. valve float. The load is taken by the clamping force and resulting frictional force between the lock and valvestem, which is provided by the spring force exerted against the 7 deg or 10 deg "incline".