The port shape and port timing are different on the 93 and newer blocks.----Soon I am going to install a newer block into a 92 and older version.----They run much nicer.
And how much are they charging you?------It may involve more than switching the powerhead.----Removing parts from blown motor.-----Inspecting those parts before installing on rebuilt.----Replacing impeller.----Test running.-----What exactly are you asking them to do ?----Why not do this simple...