Yes, block and heads will work.
'93 3.0l used a distributor, in '95 the Ranger 3.0l lost distributor and used a crank position sensor(CKP) and cam position sensor(CPS) instead.
CKP is on the front of the timing chain cover and reads teeth on the back of the crank pulley.
You will need to swap '03 timing chain cover and crank pulley over to the '93 motor, so you have a place to bolt on CKP sensor.
'93 distributor is removed and the '03 CPS/synchro will fit in that spot.
Upper and lower intake manifolds will be swapped
Oil pan and pickup tube as well
I would replace front and rear main seals(crank seals)
New oil pump wouldn't hurt
Check timing chain and tensioner when cover is off
3.0l changes over the years seen here: http://www.therangerstation.com/tech..._0-build.shtml