Stop in for a cup of coffee

so.. the only suregrip i have has 4.57 gears.. which are just too much on the street for me to listen to (thinking back to how much my 3.91s in my challenger ended up annoying me)..

Am thinking of putting in 3.55s (it's a 742 case) i have set lash on a carrier before but not changed the R&P.. only thing i'm curious about does the pinion gear have to be pressed on or are they just a tight fit? Don't have a press...