valve lock interchange dilemma

5/16 (.311") valves. 10 deg Lunati retainers. 8MM 10 deg Lunati locks. A noted eng builder told me that these Lunati locks (dont have the part # handy) that are 8mm(=.315") are not right for my 5/16 (.311") valves. The Lunati tech (old guy with extensive exp) says that they are fine & with the "funnel" effect that the clamping will be fine. But then I went ahead & ordered a set of Manley 5/16 10 deg retainers (EDIT meant to say "locks") (13151-8) (2) pkgs of eight pairs & they have lash cap reliefs which I thought would take care of things (didnt see any WO lash cap reliefs which I hear lash caps are to be avoided anyhow) & the perimeter is slightly above the tip of the valve so they wont work. This (issue) is just starting to get to me. Can I (safely) stick back with the Lunati ones??? What do YOU guys think! & if I need another set, which ones? thank you for your time. EDIT Cuz I originally called Lunati as I had mistakenly thought my valves were 8MM & I thought my retainers & keepers needed changing out & he said neither needs changing.

Not to hijack but I love and use lash caps on all my Hi Po motors

I don't know of any 8mm locks that work with anything 5/16 anything.

are the 10 degree locks +.050" or greater? looks like it to me. with those single springs I wouldn't get my panties in a bunch over using 8 degree locks.

They are "standard" height. FWIW it is ~.100" from top of lock groove in the stem to the top of the stem.

You have everything you need to determine if the parts will work together or not.

Take the lunati locks and retainer, and test fit it onto the valve.

If you can pull up on the retainer and “lock” all the pieces together(valve/locks/retainer) on the valve........as in, no wobbling, no wiggling, retainer doesn’t just fall off the locks when you take your hand off it......and you actually need to apply a little pressure to unseat the retainer off the locks........if it fits like that....... you’re good.

ANY wobbling or wiggling between any of the pieces, or if the retainer falls off when you release it........ that’s a no go.

Thank you! I'm on it tomorrow. Cab it ain't no hijack at all, any feedback is always welcome. EDIT & I have some 5/16 lash caps but they are way "deeper" than the .050" stem showing in the above pic (I'm assuming they need to set "flush"on the tip). the rocker rollers are too close to the ex side of the tips & I had considered some lash caps (maybe not what I have), some thinner ones I was thinking if that would be a smart move but one thing at a time.

Part of the reason you’re struggling with this is........ you’re “reinventing the wheel” by not using parts that are available and designed to fit those heads.

The MP springs/retainers/locks designed for use on magnum heads fit fine.

It would have cost more up front, but it would have all worked.

OK, I lifted the retainer/locks up into place then let loose & they fell right down/off. These are EQ mag heads with .311" miked 5/16 valves (bead lock "rounded" 1 groove stem). top of groove to top of stem is .120" (if that is critical to this situation). spring OD is 1&7/16. Dual springs & inner spring ID is ~.813" I dont wanna reduce the installed height & I would go .050 higher if you recommend that & not have the interference prob I have now (just sayin). my psi's are 143/308. 30 minute duration races. That is all the info I can come up with to help whether I need 7 or 10 deg etc & for reference I have Lunati 75740 retainers. Dwayne tell me what retainers/locks I need & I will order em TODAY! Thank you!

Are the lunati 8mm locks bead lock style?

As I said on the thread at fabo, for valves with the lock grooves in that location, you need locks that have the tang at the top of the lock....... like the OE locks.

You should probably read through that thread again.

The parts I installed on the EQ heads I had here recently were:
P4876062 springs
P4452032 retainers
P4529128 locks

The retainers are stupidly expensive, so I might be tempted to buy 1, take some measurements, and see if there might be a substitute for less $$$.

See if you can get the part number on what you have for springs.

Did you machine the inner step on the heads down to accommodate the dual spring?
If so, what diameter is that step now?

Dwayne thank you for the quick shout out. I am dead in the water for today. I will holler back tomorrow with the info you are requesting.