On the 261, the dowel pin has to be pushed in for full flow filtering, and the bypass filter is tapped off anywhere with full oil pressure. On a 235, the oil gallery has to be modified for full flow by plugging the oil pump output passageway below the main oil gallery and drilling and tapping a couple of large diameter ports, either 3/8" NPT or 1/2" NPT. A 3/8" fitting will carry enough oil volume to support a full flow filter and supply the engine with enough oil to keep it lubed. !/2" was a bit of overkill on the part of Chevy when they built the late model 261.
A spin on adapter fits nicely on the driver's side inner fender with single braid flex lines in and out.
Jerry
