All Small Six Cost of Building a 250ci VS 300ci

[Crustang to Mustang]

I wasn't quite sure where to post this as it involves both big and little sixes. As many of you know, I have been looking and asking around for info about performance mods for a 250ci. But due to some recent changes in my life, I feel more comfortable taking my time on getting my car running. All this being said, I had thought about swapping a 300ci into my Mustang because I love the uniqueness of it. But one big question I had: Is it any more economical to build a high performance 300ci than a 250ci?

 

[pmuller9]

As far as HIGH performance, there is far more support for the 300 six than the 250 six.
The fact that the 300 doesn’t have an integrated intake manifold and has several offerings for aftermarket two and four barrel intake manifolds is enough of a reason.

Add to that the availability of a CNC ported, big valve head with the choice of hundreds of flat tappet and ROLLER cams.
There are also aftermarket connecting rods and pistons.

The obvious advantage is the increased displacement of the 300 six.

 

[aussie7mains]

If you want something unique, then go for one of the Australia sixes. We have a 250-2v, a Crossflow head, a SOHC and DOHC Barra. Your 300 and 250 logs are very inferior to them. Just as an example a 4 litre barra NA is 195kw, thats almost 270bhp, i doubt you could get a 300 to do that without compromisings its drivability, even the SOHC 4litre was up to 172kw. You must have seen this:-

 

[pmuller9]

Just as an example a 4 litre barra NA is 195kw, thats almost 270bhp, i doubt you could get a 300 to do that without compromisings its drivability

You are behind the times.
Thanks to roller cam availability, one of the N/A performance 300 builds this year makes at least 350 hp at 5200 rpm and over 400 lb ft at 3600 rpm.
It will break the tires loose in a 6000 lb truck at 1500 rpm.

The second 300 using a Holley 500 cfm two barrel made 330 hp and just under 400 lb ft.

 

[63 Sprint]

With all due respect.

A Barra engine is fine for you guys down under. But, not here in the US. Why do you keep bringing this up? We been over this many times.

If you got the COVID shots, they have been linked to short term memory issues in some studies.

If a 250-2V crossflow head can be imported at a reasonable price, then it might be something to think about.

If high output is the goal, a roller cam is the way to go because the recent flat tappet cams and lifters are having a high failure rate when high spring pressure is needed. It would be very difficult and expensive to install a roller cam setup in a small block six.

If a 240 or 300 can be installed moderately easy. I would say it would be the way to go because roller cams can be installed. And, there is a fairly decent selection of other performance parts available for the engines.

Performance parts for the small block six are starting to fade away here in the US. They are not as popular as once as they used to be.

 

[aussie7mains]

Ive had 5 covid vacinations, and JFI, 97% of Australians have had 2 rounds. Why do I bring it up, its bragging rights I suppose. 250-2vs are still popping up but there very expensive when they do, try $3-4000 for a head and manifold only.

 

[63 Sprint]

Well, we have bragging rights here also. But myself and probably some others included would not try to push a product that is not available in different parts of the world. It’s usually best for one to use what is easily available in their part of the world.

$3,000 to $4,000 for a 250-2V head and manifold is nuts. Maybe they would be cheaper to get a set from Argentina.

I would either build a mild 250 and enjoy it as it is. It would be such an easy build and it would complement a six cylinder Mustang.

Or work on a torque monster 300 that will totally destroy any imported Barra engine running the same rpm’s at just off idle.

 

[63 Sprint]

Crusting to Mustang,
I know you were looking into a tri-carb setup back in 2023. It would look so cool having such a setup. It would certainly draw a crowd at car shows.

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The thread you started in 2023 is interesting. Some here might want to visit it. I posted your link below:

All Small Six - 3x Carburetors on 250ci

I'm trying to sort out my carb situation and I need to know, what is the overall cost of doing the Offenhauser 3x1 set up (give or take)?

fordsix.com

 

[78_200_C4]

If you want something unique, then go for one of the Australia sixes. We have a 250-2v, a Crossflow head, a SOHC and DOHC Barra. Your 300 and 250 logs are very inferior to them. Just as an example a 4 litre barra NA is 195kw, thats almost 270bhp, i doubt you could get a 300 to do that without compromisings its drivability, even the SOHC 4litre was up to 172kw. You must have seen this:-View attachment 23310

Ive had 5 covid vacinations, and JFI, 97% of Australians have had 2 rounds. Why do I bring it up, its bragging rights I suppose. 250-2vs are still popping up but there very expensive when they do, try $3-4000 for a head and manifold only.

You are making an @ss of yourself.
Maybe post your uninteresting info on the Aussie Ford Sixes forum.
My wife's Subaru or my daughters 4 cylinder Ranger would blow the doors off a 250-2V.
Log head six performance is a class like Ford model A, T or flathead V8 performance is.
Maybe find a Model A or T forum to make your jack@ss posts on.
Australia has no match for the Argentine ACTC 24 valve DOHC head that will bolt onto a Falcon high starter six.
I don't see any Australian Ford sixes racing on the Argentine ACTC circuit which can draw up to 50,000 fans per race.

​

 

[63 Sprint]

78_200_C4,
I think this is the 200 six conversion you mentioned.

This could possibly give some fresh ideas about an OHC design for the 240 or 300.
It would be lots of work and expensive.

It would be an interesting thread to start in the Hardcore Inline Tech section of the forum so we don’t muck up this thread with stuff that is available in other parts of the world.

HardCore Inline Tech

Engineering or Scientific theory. Keep it Hardcore only.

fordsix.com

The ProMaxx head for the 240 and 300 does a good job. It’s as simple as it gets to build a fun naturally aspirated big block six. And it’s in a price range that more can afford.

 

[powerband]

( ... remember we're here to share the fun of six performance enthusiasm for all its' iterations. )

"I know you were looking into a tri-carb setup back in 2023. It would look so cool having such a setup. It would certainly draw a crowd at car shows."
.
250' Comet with Tri-Power Holley 1904's may not be the fastest at the track , but may be funnest . Enthusiasts of all kinds typically engage me in animated six performance discussions at cruises and shows.

. . . .
.
hav fun

 

[63 Sprint]

Honestly, the 200 six is a neat engine. It has a much shorter deck height than a 250 and 300. My understanding is, there is enough hood clearance for a tri-carb setup when used on a 200.

A tri-carb setup on an inline six would be a great thing to see at car shows. You will have more people interested and wanting to talk to you about the setup. Most people are bored seeing V8’s. Lots are looking for something different to look at.

Speed and Horsepower is not everything. The most important thing is having enjoyment with what you have.

 

[Frank]

I wasn't quite sure where to post this as it involves both big and little sixes. As many of you know, I have been looking and asking around for info about performance mods for a 250ci. But due to some recent changes in my life, I feel more comfortable taking my time on getting my car running. All this being said, I had thought about swapping a 300ci into my Mustang because I love the uniqueness of it. But one big question I had: Is it any more economical to build a high performance 300ci than a 250ci?

As you're calculating costs/viability of converting to a 300 in a 'stang remember there are some vehicle modifications involved for fitment. If I'm not mistaken the radiator has to be moved forward, hood clearance calculations, stuff like that. The 300 is a good bit bigger, length and height.
But it's been done, and it's a cool swap.

 

[63 Sprint]

And we forgot to mention the additional weight that is put on the front end.

 

[Kritas]

deleted

 

[Crustang to Mustang]

Honestly, the 200 six is a neat engine. It has a much shorter deck height than a 250 and 300. My understanding is, there is enough hood clearance for a tri-carb setup when used on a 200.

A tri-carb setup on an inline six would be a great thing to see at car shows. You will have more people interested and wanting to talk to you about the setup. Most people are bored seeing V8’s. Lots are looking for something different to look at.

Speed and Horsepower is not everything. The most important thing is having enjoyment with what you have.

The problem is, a 250 has about a 1/2" of clearance between the top of the air cleaner and the inside of the hood. There is for sure no way I could pull of an Offy 3x1. At the time that I started that old thread, I wasn't aware of the lack of clearance yet.

 

[Crustang to Mustang]

And we forgot to mention the additional weight that is put on the front end.

The front suspension on my Mustang needs to be rebuilt anyways. If I go with the 300ci I will just upgrade to HD V8 shocks and springs.

 

[bmbm40]

Just a couple of thoughts...
A 200 with a turbo can be pretty fast and you can set the boost at level which may not grenade the engine to quickly and would certainly be easier that a 300 swap.
The 250 swap which is doable in the early Mustang and with slightly bumped up compression, 2v carb, cam and headers has power comparable to a stock 289.
Of course any turbo 200 or 250 or 300 will require new axle, suspension, larger radiator etc.

 

[Crustang to Mustang]

Just a couple of thoughts...
A 200 with a turbo can be pretty fast and you can set the boost at level which may not grenade the engine to quickly and would certainly be easier that a 300 swap.
The 250 swap which is doable in the early Mustang and with slightly bumped up compression, 2v carb, cam and headers has power comparable to a stock 289.
Of course any turbo 200 or 250 or 300 will require new axle, suspension, larger radiator etc.

I bought my Mustang with a 250 that someone crammed in there with the original 200 motor mounts. Also, I was hoping to do a N/A build. So whether I keep the 250 or get a 300, I'm faced with the same problems: clearance, suspension strength (though I've seen people who drive their 351w swapped Mustang with the original 6cyl. suspension), and larger radiator.

 

[pmuller9]

Would you be willing to do EFI on a 300?