Just passing along what I saw on the SC-650 instructions that I have.
The S-2 filter that was on my truck does have an orifice in the standpipe and a dole fitting on the supply line. But physics says that each orifice will restrict flow somewhat. As long as there's a small flow thru the filter, and sufficient oil pressure showing on the gauge, everything will be fine. The main thing to avoid is so much flow thru the filter that the pressure to the bearings and the rest of the engine isn't sufficient to lube them.
