Quickest return on investment, lift axle or ported manifold?
I am considering what improvements to make next to increase fuel economy. I am going to be getting the ported and coated manifold and bigger turbo for my 3406E CAT. I am also going to put a lift axle on my spread axle flatbed. I'm trying to decide which one will give me the quickest return on investment, so I can decide what to do first.
Is this a good question?