Where do you have the oil pressure sender attached, Deve?
Maybe you have a by-pass flow to your oil filter. That would still all oil to reach other parts of the engine. It is OK to have by-pass lubrication. Normally, the by-pass hose would be connected to the smaller diameter port to the left of the port you are using.
Here is an additional fact to add to the confusion: the full-flow filter/plumbing oil-flow direction is from left-port on block to right-port on block.
If you have not seen the "flow photo" from a Shop Manual, I'll post a link later today.
