Ok, so it's about that time to put the engine in, and I remembered that I need to replace the fuel lines. I've been looking at the ones on Pelican, but don't know what type I need 6,7, or 8 mm ID if I'm running carbs?

You'll need to measure the fitting on the carb to see what hose you'll need.

So... if it fits, use it?

Well, sort of. If it's not to loose or to tight. I recommend the high pressure stuff even with carbs in CA. The "clean" fuel we have will break down std lines and send tiny debris in to your jets IMO. The high pressure stuff has a liner in it.