Lingenfelter titanium dual spring retainer for the ZR1 Corvette LS9 cylinder heads will allow you to run the 26926-16 Competition Cams dual valve springs.
Diameter A: 1.220
Diameter B: .885
Diameter C: .643
Lock angle 7 degrees for use with stock LS9 locks
Competition Cams 26926-16 springs with Lingenfelter Titanium retainers XX04190-0016 on LS9 heads
Installed height: 1.830
Spring pressure: 135 psi @ 1.830 / 480 psi @ 1.150
Coil bind: 1.100
Max lift: .680
With a GT-9 camshaft we suggest 1.830 installed height but you could go as much as 1.810 to raise the spring pressures but it is not necessary.
Both combinations will use the Competition Cams CC511-16 valve seals & CC4695-16 spring seats.