Originally Posted by ap72
your seat pressure is of little significance here, what is your open pressure? If you have enough clearance between your retainer and seal with standard locks at peak lift then your best solution (and the free one) is to just use standard locks. I'm betting the .050" difference on the compressed height and pressure of your spring isn't going to make a bit of difference (provided you have clearance).
I hate to say this but the $240 you just spent on valves was over nothing.
The problem being discussed is:
The clearance between the self aligning rocker arm rails and the valve lock (aka, keepers). The + .050" locks does nothing to provide more clearance. The + .050" locks will lengthen the valve spring by .050", provide .050" clearance between the retainer and the valve seal and will reduce valve spring pressure. .050" x spring rate per inch.
The Manley SS valves for Vortec heads have .290" tips and will solve the problem of self aligning rocker arm to valve lock clearance. The .290" tips provide .040" clearance whereas the 1955-1995 SBC valves with .250" tips provide .000" clearance. Using 1955-1995 valves and self aligning rockers can toss the self aligning rocker arms off the valve stems, or worse.
When you are using self aligning rocker arms:
1. Must use valves with .290" tips.
2. Must avoid valve float at all costs.
3. Must use hydraulic lifters.