hey there i have a 1997 2wd f150 with a 4.2 v6. It has HIGH miles and im gonna need a new motor soon! I looked into just putting a 4.2 back in but ran in to some high prices for motors. I have heard rumors of people putting a 3.8 in and it working. If any information at all please respond or email at statefan8908@yahoo.com any information or advice is greatly appreciated

Questions:
will a 3.8 mustang motor fit, if so what has to be changed and what model motor

what other alternative motor will fit in place and what if anything has to be changed

thanks
Matthew

 

I would not go down to a 3.8. That is simply not a truck motor. If I were you I would price out a minimum 4.6 liter engine. You will have to research the wiring that is needed for it, and procure the computer controller, transmission, etc. (unless current trans will fit).
What kind of fuel economy did you get with the 4.2? I never talked to anyone that owned one of these engines before... How was the power?

 

You will go into a little more cash swapping in a V8. If you would do a V8 why bother with a 4.6L, the 5.4 is the same amount of work. The trans is a different bolt pattern and all the engine wiring has to be changed. The 4.2 is based on the 3.8, really just a 3.8 stroker. The 3.8 will bolt right in the wiring should be the same as the 4.2 being that it's just a stroked 3.8, you may want to ask around on that part. Asside from getting emissions compliance you could drop in a SBF with a set of mounts. THe 289. 302 and 351 all bolt to your current trans. Again the wiring would be different. The easiest route would be to either get a replacement 4.2 or a 3.8.

Matt

 

4.6 over 5.4 because of cost... Remember, he asked about an engine option that was cheaper than a replacement 4.2 that he has, and the 4.6 is likely cheaper than the 5.4 because there are so many around since 1994.

I would keep shopping around for a replacement 4.2 or price having a rebuild done on yours.

$1699.00 is a good price. Just Googled it at http://www.psengines.com/FORD6.htm

5 year warranty, how can you beat that?

 

putting a 4.6 in isn't going to be cheaper than dropping in a replacement engine. If he is going though the trouble and expense the 5.4 is more of a worthwhile choice. The 4.6 and the 5.4 both were F-150 engines in 97, the few earlier years of the 4.6 would work since he had a 2wd but they require even more electrical work. To do a V8 you need engine, transmission, driveshafts, and all the electronics; pretty much a complete donor vehicle. A 3.8 will probably be your cheapest option if you are junkyard shopping. There are quite a few of them. From a performance stand point the 4.2 will be better than the 3.8 due to you computer being calibrated for that particular engine, cam and so on. It's kinda like taking out a 351 to put in a 302. It will work fine but you might miss the little extra power.

Matt

 

He said he priced a new motor being put 'back in' but ran into some high prices.... reason could be one I explain below:

That's my point, I can't see a 'new' engine being cheaper than an original size replacement, except for a case that I recall, a guy across the street visiting family had an older Ford wagon, and his motor was shot... It was a V6, and for some reason, it was quite rare and not stocked by any of the engine rebuilder companies in town, so he had to wait a long tiome to have his rebuilt. Wish I could recall what engine that was!
Why wouldn't the 4.2 be a common engine? I still say, plan a reputable shop rebuild it and supply a warranty, or go with a place like the one I sent the link for.

 

A rebuilt drop in will run you around $2500 from a local parts store. Having yours rebuilt will be a little cheaper, I'd say after mill work and parts and labor $1500 or so as long as nothing is trashed. I looked at the link, that's not a bad deal as long as they deliver to a residential address. You are really better off doing a drop in engine being that it is checked and good to go with a warranty. Your block will need machining and possible other problems. If your block is trash, you're hosed. The 4.2 should be a semi-common junkyard engine; it's 10 years old. You should be able to get one for no more than $700 for just the engine and that's a high estimate. Iwould check the link and some more online. That is a pretty good deal. If you need cheaper the junkyard would be fine. If a 3.8 is all you can find it will work too.


Edit: I just remembered the link is for a long block. If you want a complete engine. Call some local shops, see what the could do for you. Try the local part stores, see how much they want. If not try the junkyards.
Matt

 

thanks guys i apprecitate all the info it was much much needed i just have one more question. i founds a 98 3.8 and was wondering if its still interchangable

 

It will bolt in no problems. There might be a few little differences with some sensors and wiring. Your computer will run it. The 4.2 is a stroked 3.8, on the outside its the same engine. You shouldn't have much trouble.

Matt

 

but its a mustang motor will that make any difference at all?

 

Granted the cam profiles will be a little different and such. I don't know about the stang computer working in a truck but it might be something to look into. Otherwise, as long as that particular 3.8 has all the same sensors or the ones from you old engine can be installed it will run.

Matt

 

You want a 97-98 Mustang engine. You'll have to change about everything, intake, exhaust manifolds, oil pan, etc. Basically you'll swap in just the "long block". One thing you have to include is the Mustang (automatic)flexplate or (5 speed)flywheel. They have to match the engine, what's in your truck won't work. The Mustang flywheel will accept the truck clutch or flexplate will bolt up to your converter. If the Mustang engine has on on it, fine. If not you'll have to buy one.
Many local folks have already done this and the salvage yards are well aware of the swap. The truck owners said they can't tell the difference, power , mileage, etc are all the same or close enough they can't tell.
Reasons for doing this are simple. Used 4.2 engines tend to be high mileage and have led hard lives, with few exceptions. Mustangs are often flung into a tree or something with low mileage. Many V6 Mustangs tend to be "girl cars". That is, fairly unabused and often well-maintained. Truck engines are more likely to have to tow and haul where a V6 Mustang likely just spent it's life tooling around. In short good truck engines are harder to find than Mustang engines.

 

thanks man i do apprecite it will the computer from my truck work with that motor

 

i have a 1997 4.2 that i converted myself to a 3.8 sc from a super coupe and it can be done and it does work awsome but u have to do a couple things for it to run rite very easy after i figured everything out it took some time to figure it out but the truck most deff. gets up and boogies now deff. a fun project and yes u can run the 4.2 computer and there is no check engine lite on and it passes emissions u can email me at miniscf150@yahoo.com if u have any questions

 

i have a 4.2 2wd 5 speed that i converted to a 3.8sc from a super coupe it works great it passes emisions and it deff. gets up n boogies if have any questions email me at miniscf150@yahoo.com