98 4.0 swap question

[Dombant]

Will older engines like 95 or 96 work in 1998? Without a lot of trouble?

 

[RonD]

Assuming you mean you are replacing a 4.0l OHV with another 4.0l OHV, if changing from another engine to a 4.0l OHV then no, there are many issues.

If just swapping 4.0l OHV block and heads then yes, no real problems.

If swapping the whole engine then you will need to change older engines fuel rail/injectors to match the 65psi '98 "no return" system.
Earlier fuel systems used 40psi with return line.
I believe the change was in the 1997 model year

Explorers were using a 4.0l SOHC around those years which is a completely different engine, Rangers used the 4.0l OHV from 1990-2000 model years