200 ci Inline-6 with headers

Olivethefet said:

Is it even possible to make good power with a 200 6 without spending loads of money? At the end of the day it's still a 200 6. For what it's worth I'd keep it all stock. Just give it a good tune up and enjoy it. If you want it to have more power then start putting together a plan to pull that old 6 out and replace it with a V8. Any V8, but I'm partial to the 289 in a vintage mustang like yours.

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yes there are a number of things that can be done on a budget to get more power from the inline six. swapping a 250 and building that is one thing you can do. select a good cam for the engine based on what you want from the engine. clay smith cams are available from vintageinlines.com, and of course comp cams has a few good ones also. clay smith will even custom grind cams at little to no extra cost. so if there is a grind you like, let them know and they can grind it for you.

going to two, two barrel carbs will also help in getting airflow into the engine. add in bigger valves, is 1.75in/1.50ex will increase airflow through the engine, and porting the exhaust and pocket porting the intake will also help. at this point you should have enough airflow through the engine that header(s) will help as well as dual exhaust, i would do 2 1/4 at most.

forced induction, specifically turbocharging, does wonders on these engine.

also dont forget to mill the head to boost the compression. for a normally aspirated engine you want 9.5:1 up to around 10.5:1 for the street. with forced induction 9:1 is about as high as you want to go and limit your boost to around 6-8psi.

wicked93gs said:

There are plenty of things you can do to an I6 to make more power. @rbohm will be able to tell you more than a few. The things I would do with an I6 are very far from stock and would completely defeat the purpose of keeping a stock low mileage engine. Generally the mild I6 guys will throw on a header, electronic ignition, and a rebuilt carb and call it a day(you don't need to change the carb, just rebuild the one you have).

For wild things you can do:

1. swap the head to the aluminum head that Classic Inlines makes....its expensive, but makes a good chunk of power(defeats the purpose in keeping it stock)

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one change here, classicinlines is no more. vintageinlines now sells the heads. he is still growing the business so he does them in batches when he gets enough deposits to make a run. i think he makes runs of 100 heads at a time.

2. swap to a different engine...either a v8 or a later Ford I6 from Australia with DOHC and 24v(again, defeats the purpose of keeping it stock)

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three heads to look for;
the aussie 250 2v head. the aluminum head was modeled after this head, with some improvements.

the aussie crossflow head, as noted requires some head and block modifications out lined in classicinlines.com tech section, the only part of that site that is still available. you can link to it from vintageinlines.com.

the argentine 188sp head. these are harder to find at least in this country, and they require a different intake than the aussie 250 2v and the aluminum head do so get that with the head otherwise you make your own.

if you can find them, and can afford them, the aussie BARA engine is starting to be imported into this country, and that is one heck of a motor as it has dohc head.

3. Boost the engine, either with a supercharger, or more efficient turbocharger.....you can do this to an otherwise stock engine and make 200+ HP fairly easily...but there are of course downsides and considerations in designing a turbo system(especially one for a carbuerated application)...this is also expensive and neither this or option 1 will be much cheaper than a v8 swap.

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a turbo system is easy enough to install, picking the right turbo for your combination is harder to do, but any turbo company will help in picking out a proper turbo for you. at that point it is a matter of matching a cam, and setting up the head to use the turbo.

5. Swap transmissions to a T5 manual trans...this makes the car both more effecient at cruise speeds, and makes the car feel snappier under acceleration...it also allows you to retain your stock low mileage engine.

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a T5 is an easy swap since there are kits for this swap. and does really help. you get two extra gears, a lower first gear and an overdrive. pick wisely though as if you get the four cylinder trans you get too much first gear making it virtually useless. the V8 trans is better imo.

6. Just like v8s, changing the gears in the rear end will also make the car accelerate faster(at the cost of higher cruiser RPM...which would be mitigated if combined with a T5). It may be hard to find 3.73 gears for a 7", but I am sure they are out there somewhere.

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again be careful picking a rear gear to run, make sure it works well wit your trans pick and the first gear you plan on running.

One day I will build a I6 Mustang.....but my plan is to use a Jaguar DOHC all aluminum I6 and slap 3 Weber sidedrafts on it(not the most reliable engine choice perhaps, but DOHC all aluminum inline 6 engines that still use a distributor are few and far between)

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good combination, i have thought of a number of engines to use, the jag inline six, the bmw inline, the nissan inline six and the supra inline six, as well as a few of the volvo inline sixes. i would most likely use EFI on these engines though for better reliability and fuel economy.

Edit, I am mostly also thinking about just enough extra zip to boost the fun factor and make sure merging onto the interstate is not a suicidal mission! That can be done without all the hassle of the V-8 swap and going too far from original.

Most domestic inline sixes were built strong enough to to be truck engines and were underpowered. I heard stories of two classmates who tried to kill off their cars from oil starvation, (one Ford and one Dodge), and driving the snot out of them. The parts were not stressed enough to be bothered. Their fathers added oil snd sent them in down the road after they cooled off. I am not surprised some NO2 would help the fun factor.

I have a flat six (that’s still in a crate for a resto mod) that instead of the stock 80hp, should have 140-150 plus Hp, plus a nice increase in torque. Not earth shattering, but will be fun in a car that’s like a solid go cart. The crate engine is bored, and has a lot of head work, block work and a custom cam. But there is no turbo with the automatic. I wish headers that will not scrape and do seal would be available because dual exhaust really helped the stock engine. The 31k mile original six is getting mothballed for the street and auto cross one in a crate. And no, it made NO financial sense to do more than swap a later 110 Hp engine in, except it’s my first car and it’s needed more power since I got it the first time.

Noobz347 said:

I dunno... I'm not thinking about enough power to set the world on fire. Just enough to give a little grunt and grumble for cruise. I don't know what all the differences are/were but I know some in-line 6 Grenada's in the '80s that took a fair amount of juice and scooted pretty well. The carb-hat situation notwithstanding, what else might get in the way?

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Noobz347 said:

I think your motor could use about 6 psi too; And not from a turbo.

Classic/Carb (1956-1975) - Ford - Small block

Classic/Carb (1956-1975) - Ford - Small block

www.thesuperchargerstore.com

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EFI and a supercharger would be cool, even though the factory flat six (it’s not a Ford this time) could have been turbocharged. I did see a NOS Judson supercharger kit for sale recently, and it sounds like any newer one would be a better idea. Making a supercharger fit with the new AC compressor could be a challenge, but there are disc brake kits to go with the upgrade.
I’ll probably leave this one at the technological level of a simple go cart and cruise it. I have many parts lined up to attack the 5.0 with after my first car is back on the road. I need to have at least one toy/often driven car on the road and reliable at a time. Subdivision covenants and my sanity requires it.

Noobz347 said:

I think your motor could use about 6 psi too; And not from a turbo.

Classic/Carb (1956-1975) - Ford - Small block

Classic/Carb (1956-1975) - Ford - Small block

www.thesuperchargerstore.com

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Superchargers, while valid power boosters...simply are not as efficient as turbochargers. The ONLY advantage they have over a turbo is that they don't add the same heat. Why in the world would you give up huge amounts of HP just to turn the blower? Centrufigal are certainly better than roots-type superchargers in that regard...but because boost scales with RPM...you might as well just use a turbo. In the case of an inline six though that have the intake and exhaust ports on the same side...heat soak is more of an issue than with crossflow heads....so it is one of the few engines I would even entertain the thought of a supercharger over a turbocharger. In the end, superchargers make more low-end torque(in the case of roots-type superchargers), but this is NOT an advantage if it causes excessive wheelspin...far better for the added torque to be mid range where its controlled easier. I will qualify that with the fact that I come from a background of cars that have a difficult time hooking up...far more so than classic mustangs at least. Think of it this way....Shelby built cars with both of them...but his turbocharged cars were smaller displacement engines....he must have agreed with Chrysler that low displacement engines were better off with turbochargers based on the GLHS, Daytona, CSX, and Charger models he built for them in the 80s.

Noobz347 said:

I don't want to beat this topic to a bloody pulp again but this is not an accurate statement. The size of the power adder, the application, the amount of parasitic loss, the time it spends within the efficiency range throughout the useable powerband, so on... The adiabatic efficiency of the entire engine combo and how it is used determines whether or not it is 'efficient'. There are plenty of examples of PD blower setups that are more "efficient" simply because they produce useable power and torque across the entire useable rpm range for more of its aggregate time than a turbo can.

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True enough...mine was a general blanket statement...but then again, so is yours. It depends on the compressor map, turbine map and type of turbo(s). A VNT or VGT turbo with correctly sized turbine and compressor wheels can make power across the entire usable powerband. It will depend on many things, not the least of which is what your engine redline is, but in general, not wasting power spinning a compressor will allow that power to be put to the ground instead. True, with a turbocharger, you do lose some potential power in greater exhaust backpressure, but not nearly as much as using the engine to spin a compressor. Did you know an Aerocharger makes full boost by 2100RPM? Its hard to argue that there is any use to power below that RPM, since the 1350RPM or so between a 750RPM idle(I personally like a 1000RPM idle myself) and full boost using a VNT turbo like Aerocharger passes so quickly that even a roots type supercharger would have a hard time showing any advantage there...besides, in the real world, adding boost at 1500RPM is just make you more likely to spin your wheels anyway(which makes you slower).

As far as carbed engines go though, its really a moot point...you only have 8-10psi to work with before carb sealing starts to become an issue and the I6 is not exactly a high performance engine with an 8000RPM redline. In the immortal words of Carrol Shelby when a journalist complained about turbo lag in the GLHS: "Son, if you got turbo lag, you ain't driving it right". Those 1000HP 4g63T DSMs running 8s in the 1/4 mile only have a few thousand RPM of usable boost with those massive turbos they run...but it doesn't stop them from running them...but I bet you if you asked those guys, not a single one would trade their turbo for a supercharger...if they did, it would make them slower.

Then there is always a third rarely-utilized option:



Twincharging using both a supercharger and a turbocharger...compound boosting that has the potential for the best of both options. Hard to say how well a carbed engine would take to it though, most likely you would have to do some serious work for the carb to retain the pressure. I have seen a total of one twincharged engine personally in my life....it was a Supercharged Ford 3.8 with a large turbo on it....sitting in a Chrysler Conquest....in the junkyard. I always wondered if it was just an unfinished project or whether he quickly overboosted and broke something in the engine. A twincharged engine though, would give you 100% coverage of the entire engine RPM range though...probably one of the hardest builds to pull off without breaking things with quite a few engineering challenges.