I am asking this because my friend just blew up his 4.2 in his truck. i pulled my 3.8 L out of my car because i am swapping in a 5.0. he is strapped for cash so i will give him the engine but i want to know if anything needs to be changed so he can run the the 3.8 in his truck temporarily?

 

Now that I'm not sure of, because for Mustangs a 4.2L is just a stroked 3.8L, but for a truck 4.2 I'm just not sure rather or not it's a stroked essex block or something else. In any since, he'll have to do a few small modifications to make it fit, because nearly all Ford engines are interchangeable.

 

Post number 18 in this thread will help you out when trying to put a 4.2L in a mustang.

https://mustangforums.com/m_2804396/tm.htm

 

almost did the same thing you did but they want to put the 3.8 into the truck.

just drop it right in. if it's a 5spd then you need the 3.8 flywheel to make sure it's balanced. Not sure on the neutral balanced 4.2 years.

you will need to swap the oil pan from the 4.2 as well as the TB and upper intake but everything else should be OK. the 3.8 will be fine in his truck. he will only have alittle less power but not really noticable in the truck unless he i loaded heavy but it still will be a good engine for him

 

Haha, as I read this again today, I saw that.