The oil gauge "sender" line is usually attached to a fitting on the lower rear of the driver's side of the block. Other attachment locations for the oil pressure sender line might be used.
If you have a by-pass oil filter, the oil pressure sender line is usually attached to a T-fitting on the lower rear of the driver's side of the block, with another line from the T-fitting going to the in-flow port on the oil filter canister.
It looks like you did not get a clear and complete answer to your question: "While we're on this top, what is the mod I see where an oil line is fed from a T in the oil pressure stem to the other side of the engine to get oil on top of the rockers?" That line from the driver-side of the engine to the middle of the passenger's side of the head is a cob-job attempt to get more oil to the rocker arm assembly. This "adaptation" might be found on 216, 235, 261 engines.
