I have in the past, had a '59 and a '62 261, and both had the plug pushed in, forcing the use of a filter or a big hunk of expensive brass that just dont work neatly. On the second one, I used something similar to a power steering hose setup, it too worked, but it was very bulky and really a pain to snake the exhaust past all the oil plumbing. On the first 261 (this was in 1962) I used a brand new genuine full flow chevy filter and hoses. but when the next 261 came around ('bout 1974), these filter assemblies were not so easy to find, so I used a bypass and no filter. I had a '54 vette intake and exhaust so the filter housing would not attach well to the more square vette intake manifold (besides it would ruin the looks of the three carb setup). With the huge diameter hose the motor would not pressure up immediately, sometimes taking 10-20 seconds to get oil pressure while the hose would "fill up", some times you could hear (or imagine to hear) a main rumbling. scary--this is why I wished you could pull out that pressed in gallery plug. Folks told me it was impossible to pull it back out. (for sure once the motor was in the car)
