RB25 Valve collet/lock question

[zachisparanoid]

Howdy! So I acquired a S1 RB25DET about a year and a half ago and after rebuilding the block its time to move to the head. Unfortunately I only have 46 half-moon valve locks...and i need 48 (24 valves, 2 locks per valve as I'm sure you all know). Looked nearly everywhere online for a pair of OEM collet's but all i can seem to find are Ferrea's replacements. Everywhere says to use these collet's with Ferrea's titanium retainers. Could i use these locks with the OEM retainers? I don't rightly have the money or the need to upgrade any head internals at the moment. If i cant use these collet's does anyone know where i can buy an OEM pair? Preciate it Nico.