When I had a 4 cyl engine, I used 12an lines to a front oil cooler. Now that I am installing a /6 are the 12an lines still acceptable? I have been told that I should use 16an lines to the main oil cooler. I would really prefer to stick with the lines that I have already- they are expensive and already installed. Is it ok to use 16an lines from the tank to the cooler and 12an on the return and front cooler hoses?

I have essentially a 2.7l non-race engine.

The -12 lines work great on my conversion with a built 2.7. If you're racing, -16 would be nice, but you'll be fine.

I agree. -12 for a 2.7