Topic: top end oil restrictors

[carsholduptraffic]

i have got the point of reassembling the head on the cb836 beast after getting the valves recut, faces decked, and new springs etc.
i noticed that this head has different oil restricters than the last (later model???) head that i used. one set is 8mm in dia with a number of holes in the tip, the other (early model??)  is 11mm in dia with what looks like a minature colander in the bottom face and a 1mm hole in top.
the reworked head needs the colander style ones, or have a substitute machined up.
any ideas on sourcing them, or will i get away with a 1mm hole in some brass bar turned to fit (i'm aware of the consequences of a blocked restrictor!)
question two: valve spring cups (seats). for reliability/performance/cost compromise- which is the pick: stock steel, aluminium, or titanium?

[Bodi]

I think a brass replacement part would be fine, make a fairly large hole through most of the length so the 1mm hole is only about 1mm long.
The restrictors mostly control the oil pressure to the rest of the engine while letting enough through to lubricate the valvegear, so the size isn't super critical. As long as your oil pressure is OK (I'd want about 40psi minimum at cruising RPM on a hot engine) and the valvegear is getting oiled it should be OK.
The "collander" is to trap any debris that would block the restrictor orifice; the holes are a bit smaller and there's a few of them so a few lumps of crud can't block it completely. The 350 & 400 have no such collander, just a single orifice... so it's probably relatively safe to do without. Make sure your engine is spotless on assembly, avoid gasket goop that could shed globs inside, always use a good oil filter and change it on schedule. The stock filter unit will bypass if the filter is desperately clogged, Terry's spin-on mod eliminates the bypass or you can replace the bypass spring with a spacer. If you keep a clean filter in there you would never use the bypass anyway though.

[MRieck]

I've got those oil jets. As for the spring seats steel is fine. As for retainers, well, titanium is the best.