Bill @ Sho-Gun says the lines are small for a reason. I use a Sho-Gun cooling system but changed to a bigger pump(I had the small Sho-Gun pump)only because the Sho-Gun pump went out. Sho-Guns bigger pump or a after market pump dose seem to work better. But I cheated and used the #10 lines with reducers at the manifold. Try it I think you will be pleased!