'87, so I'll end up needing a small pump at least for the HVAC/CruiseYou can source an electric vacuum pump that will work, but all the ones I've seen that are substantial enough cost more than a hydroboost setup! I can't remember but there was something available in the medium duty truck market. I think it was in the $400-500 range. Been a while since I looked.
When you do the hydroboost conversion just get a replacement e-pump for a mid 2000s F350 to run the HVAC controls.
What year is the truck? Pre 92 used vacuum for the cruise control and I don't know if the small e pump will work with that or not. I've never tried.