Just so no one is confused:
If you use a filter configured as a FULL FLOW on a late 261, the line size does matter. A LOT.
I initially configured my 261 with a kit I bought complete with mounting bracket for dual exhausts, a Wix 51515 filter and 3/8" SS pipe. in cold weather it took an alarmingly long time to come up to pressure -- like five minutes. I switched to 1/2" line with JIC fittings and eliminated about a dozen elbows after my first long trip. Oil pressure comes up in bout 30 seconds now with 15/40 oil in sub-freezing weather. Running oil pressure is better too.
