TOYOTA 1UZ-FE (non-VVTi). Performance Beehive spring and Titanium retainer kit to suit shim under bucket conversions. The retainer is designed to accommodate a 10mm diameter shim which are commonly available. This will allow for a cost effective way to professionally set up a racing cylinder head with modified valvetrain. This conversion kit is designed around the OEM valve tip height geometry, OEM cam base circle diameter (34mm) and OEM Toyota buckets with OEM shim (around 7.3mm total thickness). When KVS207 is used with our DLC bucket KCF-207 (3.78mm shim thickness) a 10mm shim in the 3.4mm-3.6mm thickness range is required. This is assuming OEM valve tip height and OEM cam base circle are retained. Valve spring data: 83lb seat pressure at 33.4mm installed height. 180lb at 11.0mm valve lift. Coil bind at 20.85mm.