You are kind of limited with what you can do being fuel injected but take a look at http://fordsix.com/forum/viewforum.p...25d6cb452507bc
for suggestions. This is the site I used when I built my truck last year and the knowledge is outstanding. Some small things that you can do is to side gap the plugs, add a set of headers, run free flow cats/muffler, run full synthetic lube everywhere possible, upgrade the coil to something like a MSD, change the t-stat to 195* verses factory, and clean up the cast parting lines in the runners. I believe that you can run over sized valves with the EFI but I am not sure enough to be quoted.