If I wanted to put remove the 4.0 from my 94 splash, and replace it with the 302 from my 1970 ranger,how difficult would that be? Would the V8 match up to my 5 speed manual? What electrical issues would need to be addressed? Any comments would be welcome from anyone who has done this. Thanks

 

No, transmission won't match up, '97 to '02 F-150 with V6(4.2L) will have a M5OD-R2 manual trans, it has the same bolt pattern as 302, and shifter is only an inch or two off your current M5OD-R1 placement.
You would want a 2WD version of course.

If you stick with the carb and distributor on the V8 then wiring shouldn't be an issue, no computer needed.
You will need a fuel pressure regulator as the current '94 pump uses 40psi and carb wants to see 6psi

R2 trans used to have mechanical speedometer cable like you have on the '94, but later years use VSS(electronic speed sensor) so you may need to remove the tail shft housing on the R2 and add the speedo gear back.