need some info for possible Fox Mustang swap


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I have a post going in the 240/300 forum right now, but I thought maybe I could get a little more Mustang-specific help over here. Check it out over there to see if you might be able to help me. Anyway, I have a few ?s. I'm trying to find out info on a possible 300 swap into a '87 Mustang. But I'm also trying to cover all possibilities. Just in case I decide that a big six would be too much work, a have a ? about the 250 (I know that the 200s came stock in '79-'82). Will an AOD trans bolt up to ANY 250, or just the later ones? Thanks in advance!

The 250 uses the same bellhousing as the 5.0L.

You will have to fabricate a rear sump pan as they never came stock with rear sump pans for the 250.

If you search through back posts there have been pics posted where someone modified a stock front sump pan and made it into a rear sump.

That is main reason I have not went looking for a 250 is that I will have to fabricate a rear pan.

I also like the 300 idea but I felt that was gonna be a really tight squeeze. Width is not a problem but length looked really close.
Someone here said that all you'll need is 37 inches from the firewall to the radiator bracket to fit a 300ci. Check with either Thad or maybe Fordman, they'll have the info for your swap.

I envy you Americans. As a sensible production measure, the Aussies decided all 250 and 4.1 sixes made in Geelong would only have the Borg Warner style bellhousing started in the late 60's. An AOD fits like a glove to a 250 US engine, but the Aussie 250 needs an adaptor. :cry:

:idea: So if you want a cross flow 4.1 or Aussie 2V 250, you'll just have to get an Aussie C4 with its special Aussie bellhousing, or a Toploader bell housing or post '87 T5 bellhousing to fit the American transmissions.

I've been learning all about it. Making an adaptor is a very large pain in the butt.
Hello SVO42:

I have a 81 Mustang with a 1970 250 motor in it.
My father bought it brand new in 81 (I was only 15 years old at the time)
the Mustang came with the 200 motor from factory.
When I started college my father gave me the car to drive back & forth to school.
We had a 1970 Maverick Grabber at home with the frame rotted out of it so I took the 250 motor it had and had it rebuilt with some performance goodies (Isky cam, Rhoads lifters, head work, Clifford header, ect...) :eek:

Anyway, what I thought was gonna be an easy swap wasn't. :shock:
Yes the others in this forum were right, there is no rear sump pan for a 250 motor.
I made one by using the top portion of a 250 pan and the sump portion of a 200 pan and migged the two together.
Also you cannot use the 200 motor mounts. If you do the motor will sit too hight in the engine compartment and you will need to cut a hole in the hood and add a scoop. Which you still have to do anyway as the 250 motor is 2 inches taller in the deck height than a 200.

You say you would put this in a 87 Mustang?
87's did not come with a straight 6 motor in that year. You must either have a V6 or 4 cyl. I think you will have to switch K-members with a earlier car that came with a 200 motor. All fox bodied cars had the same engine compartments so the K-members will switch.

I still have my 81 and the next plan of action is a T-5 conversion and a Holley 500 cfm 2 bbl. switch.

If you need any more info - just ask! :D


I orginally used the 200 motor mounts, but switched to the 250 mounts out of the Maverick.

The Maverick mounts will lower the engine by about 1/4 inch which is alot considering I was using the 1 bbl. from the 200 motor with a K&N open air cleaner that was only about 1.5 inches thick (in the filter area).

You couldn't go any thicker because with a 84 Mustang forward facing scoop on the hood and cutting a hole in the hood the top of the air cleaner was touching the underside of the scoop. By switching to the Maverick mounts I gained some clearance.

As far as radiator clearance - no problem at all other than you must either use a smaller fan as the stock 200 will hit the ribbing on the underside of the hood or use an electric fan. Use a rad. from a V-8 Stang. if you can.

Use a lower rad hose from a Granada with a 250 motor (because of the difference in dia.'s) the upper rad hose from the 200 motor is fine.
Right now I'm running the original C-4 that came in the car. I had to swap bell housings from the 250 as well as torque converters (I had a 2800 stall converter built)

jturcic <-- Very cool resource to exploit, er, consult.

I have a question about the oil pan-why could you not just use the 200 pan?

Yes, the '87 Mustang in question is a 2.3L. Mustangs/Cparis haven't had an inline six since '82, and even the V6s took a hiatus from '87-'93. I'm still leaning ore towards the 300, but I need to take some measurements first.

Jturcic, do you prefer the 250 or the 200? I have read on here of people who thought the 250 couldn't rev due to it's longer stroke. I like the idea of the low end torque of the 250, put a 7000 RPM redline is seems easier with a 200 (200 turbo, anyone? :eek: ). The whole "Oh, no, the stroke is too long to rev that high!" can be a little much. Just build the motor right. Look at the 2000 Mustang Cobra R. The 5.4 (DOHC in this case) has something like a 4.15" stroke. The redline on the R is 6500 RPM. Sweet, but those parts were expensive.

The 200 and 250 oil pans are not interchangeable - not even close.
The front and the back mains where the rubber portion of the oil pan gasket goes are different dia's from a 200 and 250.

If you plan on using the 300 motor, you may not have to change the K-member. It's possible the 300 is wider than a 250.

Do I prefer a 200 or 250? Well you know the old saying "theres no substitute for cubic inches" so you can go big or go home kind of thing.
For simplicity sake as far as your swap goes, the 200 is a good choice.
But if you are a glutton for punishment try the 250 or the 300.

I have my 250 built up. (Isky cam, Rhoads lifters, header, porting on the exhaust side - shaved .080" off the head, forged piston, polished connecting rods) and I can rev it easily to 6000
BUT right now in it's current configuration with the 1 bbl. anything past 4500 rpm and it's just makin' noise and no power. :(

Now, I have modified the head to fit a Holley 500 cfm and I think doing this will bring the power back that I am losing with the 1 bbl.

A quick reminder.... :!: whatever motor you choose to put into your 87 just remember to stiffen the frame in the car prior to the installation. Late model Mustangs were notorious for rusting on the tops of the 'A' pillars and putting a touquey motor in them will make it worse. At least consider tying the sub-frames together with a welded type of sub-frame connector not the bolt on type.