All Small Six I Need Some Suggestions on Pricing

[Crustang to Mustang]

I am considering swapping my 250ci for a 300ci. I wanted to know what a good price for the 250ci and its C4 transmission is. It is a '69 block with a '73 head as well as a '68 Duraspark distributor. The C4 is out of a '71 Torino and it was converted to a floor shift. The engine runs strong but needs a tune up because it runs rough when idling. I will include new gaskets. I was hoping for somewhere around $700 but I don't know much about these things. Or would I be better off selling the frame of the car that the 250ci and the C4 are installed in along with the 4 lug suspension that is up under it and the brake rebuild kit that I had bought before I decided to 5 lug?

 

[B RON CO]

Hi, $700 seems like a reasonable asking price for a complete drive train. Any "rough running" engine and I think this engine has a miss, and while a tune up can cure everything, I am thinking valve job or rebuild, especially if the engine is burning oil. I'm sure you know that the 300 is the larger truck engine. Good luck

 

[John Ha]

I paid $200 for my 73 250 with a C4. The guy I bought it from had it on Craig's List for a few months for $300 but wanted it gone. I didn't need the transmission and listed that for a few months before it finally sold for $50. There's not much demand for those parts (depending on how close you are to a big city) so expect to list it for a while. Of course, it's always easier to come down in price than up.

 

[ActionYobbo]

I paid 700 for a whole running car with a 250 &C4
You are in for a lot of work putting a 300 in a mustang. You will need to move the radiator out of the engine bay. Beef up the front suspension and add brace bars to the towers. Get a double hump pan for the motor and put a dent in the hood.
The 300 is 30 pounds heavier and 5 inches longer than the 289 v8.

 

[Crustang to Mustang]

I paid $200 for my 73 250 with a C4. The guy I bought it from had it on Craig's List for a few months for $300 but wanted it gone. I didn't need the transmission and listed that for a few months before it finally sold for $50. There's not much demand for those parts (depending on how close you are to a big city) so expect to list it for a while. Of course, it's always easier to come down in price than up.

The problem I am facing is that $200 won't even cover a third of the cost of a 300ci in my area. They run around $700 for just the running engine, not to mention at least $500 for a T5 if I can find a smoking deal. So you can kinda see what I'm up against. I don't mind adding cash but $200 isn't even a down payment.

I paid 700 for a whole running car with a 250 &C4
You are in for a lot of work putting a 300 in a mustang. You will need to move the radiator out of the engine bay. Beef up the front suspension and add brace bars to the towers. Get a double hump pan for the motor and put a dent in the hood.
The 300 is 30 pounds heavier and 5 inches longer than the 289 v8.

I am aware of the modifications that are required when performing this swap and I am prepared to meet them if I choose to go this route.

 

[Invectivus]

Yeah, I'm personally all in on the small six at this point, but I do love the 300. We had one in an 89 F150, that thing was a beast. For my own enjoyment, I hope you can go this route and keep us updated.

 

[Crustang to Mustang]

Yeah, I'm personally all in on the small six at this point, but I do love the 300. We had one in an 89 F150, that thing was a beast. For my own enjoyment, I hope you can go this route and keep us updated.

I am just trying to figure out how to get at least close to half of the cost of the 300ci and T5 from selling the 250ci and C4. But it is looking like that's not gonna happen. We'll see though

 

[Crustang to Mustang]

I would probably get $700 or close from parting out the engine but I was hoping to keep it complete for the next guy especially since it runs. If a junkyard 300ci is worth $700 shouldn't a 250ci be at least worth $500? I guess it just depends on what someone is willing to pay.

 

[ActionYobbo]

250 is a very limited market. Most mustang fixers go straight to the v8 not from 170/200 to 250. I have a 250 and a 200 and both if fitted with Aussie crossflow head and slight boost will run rings around a 4.9 or 5.0 in a mustang/falcon/ranchero on the track.

 

[Crustang to Mustang]

250 is a very limited market. Most mustang fixers go straight to the v8 not from 170/200 to 250. I have a 250 and a 200 and both if fitted with Aussie crossflow head and slight boost will run rings around a 4.9 or 5.0 in a mustang/falcon/ranchero on the track.

This is what I wanted to do in the first place but sourcing a crossflow head was difficult and even if I could find one that was reasonably priced, the Aussie cam along with the manifold and headers drain my funds.

I landed on the 300ci because parts are cheap and are easy to source here in the US.

 

[twentyover]

Couple points.

What do you want to end up with? If the crustang username is correct and you want to end up with a nice daily driver, bodywork will cost you a ton of money unless you plan to undertake it yourself. And just know it's not as easy as the youtube vids would have you believe. That's why I'm spending $40K to have my wife's MGA (cherished car, been in the family since 1973) bodywork fixed and painted, while I undertake the mechanical resto mod. I KNOW I can't give the MGA the respect the bodywork deserves, so it gets farmed out

OK, let's say for the sake of argument you want to keep the car. You want to put a 30 year old engine in it. A truck engine. And we all know how six cylinder truck engines were the darlings of fleets being driven by employees who don't give a rat's... er, fanny. So your $700 engine becomes a $2500-3000 engine by the time you knock the bores out to the next oversize (if they haven't already been bore to max oversize) and refresh the valves. Now you get to do suspension and/or changes required for the additional weight, height and probably width of the engine.

Does anyone make a swap kit? Are you a decent fabricator? While I may be interested in a 300 inch Mustang, if the swap looked like it was done with an axe and a hammer, I'd walk away. And it's not just about selling. You want respect at any car show/cruise? most people know a hatchet job when they see one. If you are a decent fabricator, delete this paragraph.

I kinda reject the implied argument that 300" parts are significantly cheaper or more available than 250 parts. True there is a larger supply base for the 300" engine (as it's attractive because of the removable intake). And you may need to wait a day or two for a 35 year old part from a supply house. And Vintage Inlines may not have parts in inventory as he's a small change (no insult intended to Matt, but he's no Speedway, Jeg's or Summit) operation intending to supply a single engine architecture. He's been focusing in the last coupla years on getting the alloy head back in production. But going to the big guys I think you'll find that parts that are available aren't significantly more expensive that 300" parts

You're not going to get a bargain basement 2V or aluminum head. More demand than supply. What you may want to do is read the tech archive and see what people are doing with the log heads. Including cutting off part of the log and building a custom intake system. What people who run this engine are hearkens back to the early days of hot rodding, where guys sat alone in their garage cuttin' and grindin' on factory parts since nothing was available. No corner speed shop (remember them?), no big manufacturers churning out speed parts. Just guys with an idea.

And I'll leave you with an example of what I'm talking about. A guy in his garage with an idea to improve carburetion on his 200" six in an MGB

 

[Crustang to Mustang]

Couple points.

What do you want to end up with? If the crustang username is correct and you want to end up with a nice daily driver, bodywork will cost you a ton of money unless you plan to undertake it yourself. And just know it's not as easy as the youtube vids would have you believe. That's why I'm spending $40K to have my wife's MGA (cherished car, been in the family since 1973) bodywork fixed and painted, while I undertake the mechanical resto mod. I KNOW I can't give the MGA the respect the bodywork deserves, so it gets farmed out

OK, let's say for the sake of argument you want to keep the car. You want to put a 30 year old engine in it. A truck engine. And we all know how six cylinder truck engines were the darlings of fleets being driven by employees who don't give a rat's... er, fanny. So your $700 engine becomes a $2500-3000 engine by the time you knock the bores out to the next oversize (if they haven't already been bore to max oversize) and refresh the valves. Now you get to do suspension and/or changes required for the additional weight, height and probably width of the engine.

Does anyone make a swap kit? Are you a decent fabricator? While I may be interested in a 300 inch Mustang, if the swap looked like it was done with an axe and a hammer, I'd walk away. And it's not just about selling. You want respect at any car show/cruise? most people know a hatchet job when they see one. If you are a decent fabricator, delete this paragraph.

I kinda reject the implied argument that 300" parts are significantly cheaper or more available than 250 parts. True there is a larger supply base for the 300" engine (as it's attractive because of the removable intake). And you may need to wait a day or two for a 35 year old part from a supply house. And Vintage Inlines may not have parts in inventory as he's a small change (no insult intended to Matt, but he's no Speedway, Jeg's or Summit) operation intending to supply a single engine architecture. He's been focusing in the last coupla years on getting the alloy head back in production. But going to the big guys I think you'll find that parts that are available aren't significantly more expensive that 300" parts

You're not going to get a bargain basement 2V or aluminum head. More demand than supply. What you may want to do is read the tech archive and see what people are doing with the log heads. Including cutting off part of the log and building a custom intake system. What people who run this engine are hearkens back to the early days of hot rodding, where guys sat alone in their garage cuttin' and grindin' on factory parts since nothing was available. No corner speed shop (remember them?), no big manufacturers churning out speed parts. Just guys with an idea.

And I'll leave you with an example of what I'm talking about. A guy in his garage with an idea to improve carburetion on his 200" six in an MGB

I see what you are saying about the condition of one of these engines and that is some good stuff I hadn't necessarily considered.

From what I've read on here and on other sites (someone correct me if I'm wrong), is that no major fabrication is needed to swap a 300ci (especially if I plan on running EFI) into a Mustang except for maybe a cowl hood and people have managed without even that. It is relatively easy to turn a stock hood into a cowl hood especially when you have multiple friends who are experienced welders and one of them owes me favors.

I'm wasn't implying that US parts for a Falcon six are more expensive and harder to find than 300ci parts. I was specifically responding to the suggestion that I get a 250 Xflow head and in doing so having to get Australian headers, an Australian intake manifold, and an Australian camshaft. It is hard to find Aussie parts in the US but when you do they are pretty expensive. This was my meaning.

I have considered cutting out a section in the middle of the log and welding in a steel "box" that I could mount a 4bbl carb on. Of course I would blend it some so as not to create more 90 degree angles in the intake.

But if I were to keep the 250, I would need the proper mounts that I haven't been able to find anywhere.

 

[bmbm40]

Here is some detailed inform from John Ha on how he modified his existing mounts for the 250 in his 1966 Mustang.

250ci Post in thread 'Alternatives for Maverick Mounts?'

Feb 10, 2024

Here is what I ended up doing with mine when I put a 250 in my 66 convertible. The engine mount was the most time-consuming issue to resolve. In the end, I used the stock perches (the part that attaches to the frame), the stock mount/isolator pieces that attach to the 200 engine, and a couple of pieces of heavy steel to act as lowering blocks.

I drilled a hole in each of the isolator brackets between the holes that were already in there. I also drilled 4 holes in the steel spacer, using the stock isolator holes as a template. Then I welded a bolt to the spacer on the side that would...

• John Ha

• 

 

[bmbm40]

This is info on member CoupeBoy who might make some 250 mounts:

All Small Six Post in thread 'i6 250'

Apr 23, 2025

He reached out to me through a PM and I've responded.
I do make mounts.
I'm not terribly fast
If you need some let me know, but also let me know what you are working on as far as the vehicle and when you need them.

• CoupeBoy

• 

 

[drag-200stang]

He has a 250 in his car now, he does not need to put a 250 in . He would like to put a 300 in.

 

[bmbm40]

He has a 250 in his car now, he does not need to put a 250 in . He would like to put a 300 in.

OK thanks.
I was responding to this OP statement in post #12:
"But if I were to keep the 250, I would need the proper mounts that I haven't been able to find anywhere."

 

[Crustang to Mustang]

He has a 250 in his car now, he does not need to put a 250 in . He would like to put a 300 in.

It will pretty much be a complete swap either way because I got a 5 lug donor car that I will be putting whatever engine in. Whether I am pulling the 250ci out of the old car or get something else.

 

[awasson]

What’s your goal for the car? Is it going to be a weekend warrior car that comes out on cruises and things like that, a race car or are you looking for a dependable but fun Mustang?

Your car looks like a 66 but I can’t tell for sure. I’m on a path with a mildly done 200 with a carb and it’s nothing but fun but I think if it were me to do your car, I’d stick with the 250 and get some mounts made up or put in a 200 and I’d fuel inject it with a sniper or something like a sniper. For a bunch more fun, I’d boost it. You could bolt on a Paxton or go turbo and I’ll be it would cost less than finding a 300, sorting it out and then shoehorning it in.

 

[Crustang to Mustang]

What’s your goal for the car? Is it going to be a weekend warrior car that comes out on cruises and things like that, a race car or are you looking for a dependable but fun Mustang?

Your car looks like a 66 but I can’t tell for sure. I’m on a path with a mildly done 200 with a carb and it’s nothing but fun but I think if it were me to do your car, I’d stick with the 250 and get some mounts made up or put in a 200 and I’d fuel inject it with a sniper or something like a sniper. For a bunch more fun, I’d boost it. You could bolt on a Paxton or go turbo and I’ll be it would cost less than finding a 300, sorting it out and then shoehorning it in.

At this point I am looking to have just a fun street car that I could drive daily if I wanted/needed.

My car will end up being a collage of a '65 and a '66.

My brother-in-law has a turbo and intercooler that he had installed on his 2.4L 1987 4Runner. He said I could have them if I wanted them. Anybody know if one of these turbos will work?

 

[awasson]

At this point I am looking to have just a fun street car that I could drive daily if I wanted/needed.

My car will end up being a collage of a '65 and a '66.

My brother-in-law has a turbo and intercooler that he had installed on his 2.4L 1987 4Runner. He said I could have them if I wanted them. Anybody know if one of these turbos will work?

If I was doing a 65/66 mustang with a turbo 300, I'd measure out that 300, height, width, length and weight and see what I'd need to do to make it fit. I've seen some video of a 66 Mustang with one but I don't know how they shoehorned it in. Maybe they pulled the firewall back and they definitely had custom mounts. It's just such a big engine. I think you'd want to swap to a Mustang II front end to handle the weight and get some decent brakes under yourself.

I'm leaning towards a turbo, inter-cooled 200 myself which I think will be much simpler. My engine is done and is pretty snappy naturally aspirated with a Weber 38/38, header cam, HEI + 5-speed. I'll add fuel injection and a turbo to complete the package. I'll beef up my suspension, steering and brakes. It's getting power brakes and probably coil overs. Quick ratio 16:1 steering box. Export brace and Montecarlo bar. Discs front and probably drums back. Some sort of upgrade to the rear suspension. I intend to find an Explorer 8.8" rear end and drive shaft and shorten the driver's side and run a pair of passenger side axles. That makes the pumpkin centered and makes the width correct for the 66 Mustang. I think that will be tough enough for anything the little 6 can throw at it.

There are certainly more knowledgeable people here who can advise you on the size of the turbo but from what I've been able to read up so far, a T3 sized flange with a 60mm compressor is a good place to start for the small six. At least that's what I've read about the 200. Here's an interesting discussion on the subject: https://fordsix.com/threads/idiots-guide-to-turbocharging-the-falcon-6.48100/