51Greenmachine,

Do you know what year 261 you have?
The 1958-1962 had large 1/2" NPT oil line fittings on the intake/exhaust side of the block. The 1954-1957 261 had the smaller oil filter lines (as on the 235) on the intake/exhaust side of the block.

I have a 1960 with a spin-on filter adapter (on the intake/exhaust side of the block, where the original oil filter had been installed).

The line that I think 53moneypit refers to is on the distributor side of the engine, and, as he posted, it feeds the rocker arm (and is not normally not used to feed either an oil filter or oil pressure gauge, but some people have done this).

Did you engine have a canister-style oil filter or did the engine originally have no filter?

Post here the size of your oil lines and I will post a few pictures of small oil lines or big oil lines.

The oil pressure gauge line is usually attached to a "T" fitting on the inlet side of the oil filter. Where was it originally attached to the head/block on your engine?

Tim

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.