Then you should know what you are getting into if you do decide to go with a V8.
How much time and $$$ you put into your V8 conversion depends on alot of things.
First, what will the truck be used for once completed?
Do you have to pass state emissions requirements?
What transmission do you want?
Do you want to keep air conditioning, cruise control, etc.
These drive what 5.0L drivetrain you choose to swap in.
That desicion determines how much $$$ you are oging to spend
Then you decide if you want to chop up the truck to fit it in there (notch the frame, modify the radiator core support, fab a trans x member, hammer the firewall, notch the heater plenum, etc)
Basically all 5.0L conversions into your 94 truck will require:
dual sump oil pan
oil filter re-location
custom/mustang engine mounts
trans mount re-location
heater plenum notch
serpentine front dress on the 5.0L
custom radiator/chopped core support
exhaust manifolds/headers
then you have to figure out what trans you want behind the 5.0L and how/if it mates to your transfer case. Figure out how to shift it
Then there is engine/trans controls.
Carbed? EFI? MAS? etc....
Plan to spend anywhere from $2000-15000 to complete the conversion.
Can take from 2 weeks to two years.
You see without searching your options are all over the map.
If you plan to attempt this then you should KNOW what you are getting into and why.
You should research the heck out of your options, luckily when it comes to putting a 5.0L into a Ranger or Explorer it has ALL BEEN DONE and it is covered online with pictures, but you need to have a starting point.