200, 250, or 300 i6?

Relicsrule said:

I have a 200 six in my 68. Its been balanced has a mild cam classic inline alum head full roller rockers (tera yellow) holly 390 cfm carb. running on the high way at 60 it gets 17 mpg. When you step into it really moves out.That said it is not about mpg as I could of built a v8 for half the money and used the savings for years of gas. most people like it because it is different. Dave

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Aariley5 said:

Keeping the 351w and adding a 23 gal. Fuel tank is a no go for me, heres why, I’m not trying to make it fast or peppy, I want it to behave like the old goat that it is. 351s are notoriously hard to keep cool in broncos especially going slow in the snow (something I’ll likely do a lot of). Also I don’t want the 23 gallon tank because of how far they hang down, I think it looks awful that’s just my opinion though.

I’m not worried about hurting the value because I don’t plan on selling it, the bronco has been in my family for a long time and was designated as mine when I was a kid. It’s just a project that I’m getting closer to finally moving on. The plan is to get it up and running again with the 351w first and if I love it I’ll keep it in there, but most likely I’ll swap it. My first car was a 69 mustang with a 351w and it was fun but it got about 8mpg driving conservatively, not fun on the wallet.

The tires I will have on it will most likely be 31s or possibly 33 10.50s. I like the skinny tires.

I have talked directly with several owners of late 70s and early 80s pickups with 300s in them (2wd and 4x4 trucks) that say they get 18 mpg +. But I have also heard from plenty of people that get no better than 12 mpg with the 300/4.9 as well...

I also have read a ton about these motors and have read through just about every thread on them. Mostly I’m just looking for insight from people who actually have them or have had them in broncos. I’m curious about the differences between 200, 250, and 300 and why someone would choose one over the other.


A lot of v8 owners seem to put down the i6 based on what they’ve heard or read. But, I’m a big fan of i6s in general. I like the toughness, simplicity, and reliability..also the novelty.

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DirtDonk said:

What some of them are saying about the 300 being a pain is that it's physically larger than what would fit easily into a Bronco engine compartment. There are a few members that have done them, but there is a lot of cutting and welding involved.
Moving radiators forward, cutting firewalls, and stuff like that.
Most that are looking to go with a six would prefer having the 300, especially if they've used them before. But for ease of installation, the smaller engines have the advantage.

The mounting towers are available new and are relatively easy to install.
Not sure what the other differences are, or whether one feature gives a particular engine a leg up over the other.
But most of the six-cylinder owners that are not as familiar with sixes and their particular power bands as you are, end up changing them out for V8's. The factory Bronco engines (170 and 200) were never much on power compared to the 300.
I think the 250 was a popular swap for awhile, because it was larger than a 200 and had the 302 bell housing pattern and was not as physically large as a 300.
But it still did not have the power on tap, so was naturally less popular than going the other direction.

I hear what you're saying. There just aren't as many I-6 owners here as there are V8 owners. Hopefully some of the sixers will see this and chime in with what they've done.
Frankly I'm very interested in what fuel mileage you get after you get it worked out.

Good luck.

Paul

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Aariley5 said:

I appreciate all the great info everyone!
I am still deciding between the 200 and 300 inline.
I’m not looking for lots of power so I wouldn’t mind going with the 200 and driving slower, A bronco isn’t the vehicle I’m going to want to go fast in anyways. I won’t swap a 302 no matter how much everyone else likes them. I understand they’re great for the broncos. But like I’ve said before I’m going with an i6. Not just for higher mpg. Also because I just like i6’s, for a lot of different reasons. V8 guys may not understand. But theres just something about straight 6 motors... things I’m worried about.. finding i6 frame mounts..and if I find a 200 someone took out of a car, finding a bronco oil pan..

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blubuckaroo said:

I can appreciate someone doing their own build, the way they like, and not at someone else's whims.
I've been running into a similar issue. I've got a '62 Ranchero project. It was previously converted to a 289 V8 from a 170 six cylinder.
I'm converting it back to a six, and I've received lots of ridicule.
I already have enough V8 vehicles. I just love the sound of a healthy inline six.
What's wrong with doing what you want with your own vehicle?

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hellabadbroncos said:

Just add a self learning efi system so itll run efficiently and at optimal performance. Should gain mpgs aswell. look at proflow4

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blubuckaroo said:

I've been doing some research on this, and can't understand why Ford didn't use the 200 in a Bronco until 1973, but started using it in Mustangs and Falcons in 1965. ?:?
The 144, 170, and the earlier 200's are pretty much interchangeable.

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blubuckaroo said:

I've been doing some research on this, and can't understand why Ford didn't use the 200 in a Bronco until 1973, but started using it in Mustangs and Falcons in 1965. ?:?
The 144, 170, and the earlier 200's are pretty much interchangeable.

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