the item you linked goes in the intake of the V8 - there is nothing similar for the 6, the oil is 'filled' into a hole in the valve cover that has a simple cap on it .... you must be seeing the road draft tube opening on your 235, which is in the block just above the oil pan, sometimes called the crankcase ventilator - it's not reproduced that I know of, you'll be looking for used

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics