I am currently replacing engine in 91 F-250 with a 5.8 and I am removing smog stuff. I am going to leave all the electical connections in to keep CEL off but my question is can I remove all the vacuum hoses from the diverter valves that sit over drivers side V/C without making it do anything crazy.

 

You can safely remove all the air injection plumbing and remove or cap the vacuum lines that fed those valves, but don't forget to plug where it connected to the exhaust or you will have a problem, there should be no leaks in the exhaust upstream of the O2 sensor. The EGR system cannot be eliminated without setting codes but it's just 1 valve and vacuum line so it's not that bad.

 

So I have to leave the vacuum line that goes to the egr valve in place or it will set a code? As far as exhaust it's getting a completely new system...long tubes and dual all the way back

 

I would be leery about disabling the egr valve as that can cause pinging.