Mr Cig,
I would think -12 or 3/4" ID would be more than enough to flow to the manifold. Check out the thermostat outlet and the water inlet on the manifold. They are almost certainly pipe thread, probably 1/2" NPT or maybe 3/4" NPT. Buy the adapters, NPT to JIC fittings, either -12 or -16 and the hose and appropriate fittings. The majority of restriction will come from the thermostat outlet even with a -12 hose.
BTW, don't mix up SAE and JIC hydraulic fittings.

Kelly,
Like he said, Summit or JEGS has them as kits with the S/S hose sleeve and anodized clamp covers. The best price I've seen was in J C Whitney. They sell aluminum braid hose covers that look just as good for less than 1/2 the price and are easier to work with.

Gary, thanks for the tip. I had priced the real hoses and stuff a long time ago and dropped that idea when I figured out what it would run me!!

I didn't even know there were sleeves available, and didn't know where to start looking. I'll check out JC Whitney and the others. Thanks again for the info.

Mark,

Let me know what you find out, and how they sell it. When I put the headers on it made my hose to short and I had to extend it. I have wanted to switch to braided since. I'm sure it come by the foot. Winners circle had it in Joliet, I ordered it and after 3 weeks of not comming in I cancelled it and never got it.

I E-mailed Earls and he said that -18 part#300018 is equivalent to 1"I.D. hose.
I am going to call Summit Racing for a price.