-4 line will be plenty. One thing for sure you MUST do is restrict the oil to the top. I run mine through the bulkhead of the block and split to each side. This way my restricter is outside where I can change it. I have an idle air bleed at .060 which will amaze you how much oil will get thru there. Straight full time oiling from the galley will flood the heads and empty the pan. Not good.

RIP