Debating a 4.0L SOHC/5.0L motor swap…input is appreciated

I currently have a 4.0L OHV sitting in my engine bay. I has 200k on it and a blown lower intake gasket.

I bought the gasket from Ford and started tearing apart the top of the motor when I realized the valve covers gotta come off. After seeing this I started thinking about changing springs, valves, lifters, rods, perhaps just replacing the entire heads with Alabama ones which I was quoted $185 a piece, upgrading to a 410 cam, etc. 'while I'm in there' when I realized I might as well rebuild/replace the motor since I would most likely blow a ring or a bearing after replacing all the upper half of the motor.

The gasket direct from Ford:


Which brings me to my question...should I rebuild the OHV or swap the motor?

Pros to the OHV -
-The most robust and reliable motor I have ever had the pleasure of provoking a controlled burn in.
-Better compression ratio for supercharing - If I kept the OHV I would rebuild with the intent of supercharging.
-Lifetime warranty on the 4r55e via Aamco.

Cons -
-Lack of an abundance in aftermarket parts (ie. heads).
-Lack of horsepower.
-A pretty expensive rebuild if done right ie. Creager's rebuild.

and this leads to further dilema - SOHC or v8?

Pros to the SOHC -
-lifetime warrany on my 4r55e with Aamco (they are in something like 40/50 states, very convient!) assuming the trans will bolt up to a SOHC.
-I shouldn't have to change the ECU (from what I have read the only difference is an additional sensor on the motor, can't remember what sensor. Perhaps a cam position sensor?)
-Better gas milage. This is a big one for me!

Cons to the SOHC -
-I would need to find one newer than an '03 or one with low milage and spend more money on rebuilding the timing chain tensioners.
-Higher compression ratios are not good for supercharging
-Lack of aftermarket parts??? I'm not sure of this one, I don't think it should be too much of a problem since the 245ci motor is now found in the non GT stangs, right?

Pros to the 5.0L v8
-Hmmm well it's a 5.0! I think we all know most of the pros to this motor.
-A better trans (not really an issue since I have the Aamco warrranty)

Cons to the 5.0L v8
-Loss of a $750 lifetime warranty.
-Gas milage!!!! It's my daily driver.

So what yall think?

i would rebuild the ohv or drop in a 5.0l

The SOHC would definitely be easier than a 5.0 if all you have to change is the motor.

Otherwise, it's exhaust, radiator, air filter and tube, coolant over-flow and washer fluid tanks, fuel lines?, etc, etc, etc.

ugh forgot about all the 'little' things.

I will be looking a lot more into this SOHC swap.

The 5.0 is lookin pretty sexy cuz this woman totaled her truck (driver side front corner hit). It's a '97 5.0L AWD. Shes thinking about buying my other '97 5.0 AWD since it's exactly like hers execpt for the color. I offered to make her a deal if she bought hers back from the insurance for $800.

But then you gotta add the cost of the AA part. Somewhere in the range of $500 right?

My cheapest option would be to just change the gasket and see how much longer the motor lasts. No performance mods tho

You dont have to screw with the valves and heads to change the lower intake gasket. Just pull the valve covers off and pull the lower intake and replace the gasket. Seams like a waste to me to throw the motor out when less a $100 in parts could easily fix the motor. I say put the gasket in and see if it fixes it. If it does great keep driving it and start saving for a new motor. If it doesnt then break out Visa and put a new motor in.

Another option I have would be to pull the OHV and swap for another OHV/SOHC while I rebuild it. Maybe installing SOHC pistons in the rebuild for better milage?

RockRanger said:

You dont have to screw with the valves and heads to change the lower intake gasket. Just pull the valve covers off and pull the lower intake and replace the gasket. Seams like a waste to me to throw the motor out when less a $100 in parts could easily fix the motor. I say put the gasket in and see if it fixes it. If it does great keep driving it and start saving for a new motor. If it doesnt then break out Visa and put a new motor in.

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This is the route I was planning on taking. I didn't know the valve covers had to come off. When I saw this and realized I needed to spend another $20-$40 in gaskets I thought to myself, why not replace/rebuild springs, valves, lifters, etc. Then I started thinking about the rods and cam and unfortunately I just kept thinking of stuff to replace lol!

I think I will probably patch her up for now and start building another motor, perhaps a SOHC.

I've got a set of 4.0 OHV valve cover gaskets, that came with my upper intake set. I never had to use them, and won't need them again in the foreseeable future. (My Ex developed a fuel leak and then caught on fire). You can have them for the cost of shipping. They are Victor gaskets from carquest. Cork, with a steel layer sandwiched between.

wow this thread is interesting.
I am with RockRanger on this one.

$800 for a complete 97 5.0L truck is a HELL OF A DEAL and basically you would have everything you need to convert your 96 to a V8. Forget about the SOHC conversion, you are just opening a can of worms, its the same $$$ (likely more since you can get a 5.0L truck for cheap) and amount of work so why go SOHC unless you have one laying around, complete with computer, etc.....

Fix your OHV 200K miles is half life n the block if it was maintained and kept cool

Start planning for the V8 if you see it in your future, but PLANNING is key, because it sounds like this is your DD.

seafarer76, thanks a bunch and I really apprecaite the offer. The thing is, If I'm going to patch her up, I'd like to go a head and take care of it this weekend. Especially if this woman wants to trade with some cash for my '97 5.0L cause I won't have a ride after I sell it.

Ford up the street has the gaskets in stock for $27 a piece and will sell them to me at 40 bucks for both. I'm a frequent buyer there.

I just called the woman about the wrecked 5.0; she has yet to get a call back from the insurance who is suppose to call her by the end of today.

The only thing I'm worried about is the fact that the motor and trans have 124k miles on them. I haven't seen this truck yet running so I don't know what sorta shape it is in mechanically.

I'll keep you all posted when I get an update from her about the truck.

r37ribution said:

The only thing I'm worried about is the fact that the motor and trans have 124k miles on them. I haven't seen this truck yet running so I don't know what sorta shape it is in mechanically.

I'll keep you all posted when I get an update from her about the truck.

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well it had to be running to get hit....just a thought. I have 120k on my 5.0 never been touched tranny or engine and it is still real strong.....I would not even think twice about it with that many miles.

Yeah, your prolly right.

My '97 5.0 that I'm tryin to sell to her has 128k on it and it's beautiful. I almost wanna total my 5.0 out so I can use its drive train. Oh how I wish an F150 would back into where the front and rear doors meet in a parking lot or something. Or even a very minor t-bone on the passenger side with just me in it lol.

I mean the tranny was spotless when I dropped the pan, there was bearly anything on the magnet and the fluid was nice and red. It even had the plug in it still, so I don't think the filter had been changed before; I was shocked at its condition.

The mpg, weight, and warranty for the trans if I got the SOHC route all sound very nice right now though.

Resurrecting this one...

So I swapped out the lower intake gasket only to find out my heads were cracked as well and the truck has just been sitting around since about a month after I changed the gasket.

I don't want to replace the heads only to have to do the lower half of the motor soon down the road so out the motor will come. My torque converter is shot and mounts wouldn't hurt at 203k either so I gotta pull it all apart anyways.

I have decided on a 4.0 SOHC swap for my '96 and I need to know what I am not thinking of here:

4.0 SOHC motor
ECU
pin added to the wiring harness for the cam position sensor

I have read that PATS is a problem in 98+ ECUs, so I'll need a 4.0 SOHC ECU from 97? Also read from someone who did a similar conversion that one of the bolts in the bolt pattern on the bell housing is different for a newer 4.0 SOHC matted to a 5r55e but is the same on older 4.0 SOHC 4r55e and 5r55e but I am unsure of the years. This was done for interchangability on the line possibly? Unfortunately I can't find the post. So I'll need the good SOHC from a 2002+ and possibly a bell housing from an earlier year. Does anyone know this to be true?

Overall this doesn't sound as hard as everyone is making it sound to be, but I'm probably missing something...

BTW, if anyone has a recommendation of a good performance torque converter I'm open to suggestions.

If your trans will bolt up lacking just one bolt I wouldnt be hugley concerned about it, it will hold with 7 bolts.

In fact with your transmission I would not plan on doing any ADDITIONAL wiring, meaning I would not plan to use the SOHC computer with your new engine, instead I would run the SOHC tranny using your OHV computer because your current computer controls your transmission.

Your 96 should use a return style fuel system, so if you get a later model SOHC donor with the returnless style, you will need a 97 ish SOHC fuel rail setup/intake

Other then that it is pretty straight forward, you will have to do alot of wiring, basically making your current OHV wiring harness fit the new SOHC and sensors.
Being a 96 truck the SOHC should pretty much bolt in place as long as you get all the parts you need.

With that said this is alot of work, this is not a project you can plan to jsut complete over a weekend, thats not to say it cannot be done, but in my experience there is always SOMETHING that will delay you and cost you more $$$ and headaches

As with any drivetrain conversion, the absolute best thing you can do for yourself is get all the parts you need from a single donor, in one shot.

410Fortune said:

In fact with your transmission I would not plan on doing any ADDITIONAL wiring, meaning I would not plan to use the SOHC computer with your new engine, instead I would run the SOHC tranny using your OHV computer because your current computer controls your transmission.

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Could you elaborate a little? I'm planning on keeping my current 4R55E as it was just rebuilt. Are you saying keep my current computer or get a new one? If I keep my current ECU won't that be a problem because it doesn't have a cam input?

As far as the wiring harness goes, I was hoping to just change the pinout on the SOHC harness to match my OHV pinout.

Good info on the fuel setup, I'll look for a SOHC with a complete intake/fuel rails.

:edit: I could be wrong about the whole cam input thing, I remember reading it a while back. I guess it could just be missing from the wiring harness and still be on the ECU but at a minimum I think I would need to request new code from Doug904.

Your transmission is controlled by the computer you have now, so using a SOHC computer will likely require you to use a new transmission

UNLESS the 96 and 97 auto transmissions are 100% the same from OHV to SOHC, then you can use a 97 SOHC computer.

I personally would keep my OHV computer and use it to run the SOHC engine, you ignore the cam position sensor, see Brett's conversion thread

Your OHV computer will run a SOHC engine and the truck or engine will not know the difference.

You need a 97-98 SOHC fuel rail and intake I believe, in 99 they are return less style and fuel pressure is computer controlled

I want to see a V8 swap from the beginning to the end.


Go V8! My 2 cents.

99sportx is getting ready to post up his v-8 swap into a sport writeup

it is very informative and well documented--and-he has the good v-6 driveline for sale---

Jakee said:

I want to see a V8 swap from the beginning to the end.


Go V8! My 2 cents.

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I would absolutly love this as well, but my deal for the wrecked 5.0 I talked about earlier in this thread fell through.

Right now I'm thinking about what is most cost effective for myself...

for the 5.0 swap I would need:
1. 5.0
2. 4R70W
3. AA's 4R70W to t-case adaptor
4. 5.0 ECU
5. Modify the t-case cross member
6. wiring
7. exhaust
8. and I don't remember what else off the top of my head...but I'm sure there is something I left out

and the SOHC swap:
1. 2002+ 4.0 SOHC (the good one)
2. 97-98 fuel rail & intake
3. Possbily an ECU
4. wiring
5. exhaust
6. again, the forgotten extras...


I have weighed my options and I really think the SOHC swap will not be difficult, will be significantly cheaper, I'll get better milage, and I'll keep my LIFETIME warranty on my trans. Not to mention the SOHC is still used in new explorers and mustangs so there should be parts support for some time to come.

I use to own a '97 SOHC Sport and I was quite pleased with the power down low and up high in compairison to my OHV. It was a very smooth running motor. I currently have a '97 5.0 and my MPG is ~15. Honestly, the power in the stock 5.0 wasn't much different from the SOHC.

Now this won't be my DD except for in the winter so MPG is just an added bonus that does not play a critical part in my decision.

A few things which add to the cost of a 5.0 swap...
-I have already spent $280 on a custom high capacity drive shaft and would need to shorten that.
-I probably would need to re-gear from my 4.56s to a 4.10 or higher.