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Trying to finish it
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Discussion Starter · #1 ·
I just bought my bronco a month ago and i've been thinking. should i stay with my straight six with 130,000 on it and rebuild it for more horsepower. or shoul i swap in a 350 or even a 460? My second question is if I do swap engines do i or should i swap the tranny and axels. I need some help, first Ford ever. I drive chevy's more often.
 

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Enjoy my
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If you put a 350 in that god WILL strike you down.
 

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For starters, my Bronco pretty much fell into my lap (it was given to me) and it came with the 300. It was my first truck and my first Ford. I thought it was a ridiculous idea to have a six cylinder in a truck and planned on doing what you are with swapping in a V8. However, over two years later I still have the 300 in there and have no plans on getting rid of it.

As many will attest to, the 300 is an awesome engine. They're strong, durable, and usually get 300,000 miles or more if you take care of them right. I wouldn't even sweat a concern of your 130k unless it's very obvious it's been abused.

Secondly, swapping from a I6 to a V8 is a bit more work than swapping from one (302, 351, 400, or 460) V8 to another. You have to change engine mounts and things (and even more if you have an EFI version with computers and stuff.) However, transmissions and axles all match up just fine, some are just more recommended than others.

For less money and a lot less work than you could swap in a V8 (unless it's given to you), you can build the 300 with plenty of power and performance to make you happy (unless you're wanting gobs of gut wrenching power, then yeah, a V8 is for you) and you'll usually score better gas mileage. A timidly driven 300 can get 20+ mpg on the open freeway.

The questions you need to answer are:
A) what you want out of your truck and what do you want to use it for?
B) how much money are you wanting to spend?
C) is your 300 carbed or EFI and what year is it?

If you keep the 300, you won't be disappointed. It is a true truck engine and will take you anywhere and everywhere, just not as fast as some other engines. :) They're also very easy to maintain and work on and are very reliable.
 

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It all depends on what you want to do. If you want a fire breathing HP monter, then the 300 isn't for you. If you just want something that is reliable, gets decent mileage, and has low-mainteance, keep the 300.
 

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Call an amberlamps!
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if you swap the engine plan on swaping the tranny with it, I would go with a 351 they are a bit easier to trick out. Although the 302 gets better gas and is still a great engine...

Its all prefrence
 

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Trying to finish it
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Discussion Starter · #8 ·
Sorry, forgot to put the 1 after 351. I do know that a 300 will run forever, however i want to know how much horsepower it can pump out without nitrous. I did have a 4.3 ZR2 and never got stuck with it and I put that thing through hell (when i went to trade it in for my Silverado, the salesman laughed).

It's an EFI, to whomever asked that question.

The Bronco is going to be a work truck on my farm, fishing, hunting, camping, mudder, and beer runner. I plan on making my own bumpers, spare mount is possible. But the engine needs an oil gasket, which won't get here for 2 weeks, and i practically live next to summit racing. And i need to clean the engine up some and flush the radiator.

I do plan on a 4 inch suspension coil over with add a leafs on 35 inch tires.
 

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Stick with the 300, it won't fail you. It doesn't sound like you need a v8 anyway. I get the impression you want one! :shrug

Now of course who doesn't love the growl of a v8. :rockon:rockon
:beer
D
 

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if you swap the engine plan on swaping the tranny with it, I would go with a 351 they are a bit easier to trick out. Although the 302 gets better gas and is still a great engine...

Its all prefrence
Why would you need to swap the tranny? The six uses the same bell pattern as a 302/351.
 

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I have a 300-6 pushing my 79 Bronc, 35" with 3.50. Yea I could switch the gears, and yes the 300 is solid but bronco's are heavy and tires in the mud need power. Yea switch it over, as for myself I am installing a 400 (Propane).

The straight six are poor on fuel, had (3) 300-6 motors in different vehicals, 2 Carb and 1 fuel injected.

Good luck!
 

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Trying to finish it
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Discussion Starter · #12 ·
My bronco is a manual to which is kinda hard to find a truck that is a manual anymore, at least where i live. thanks for the info.
 

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I have a 300-6 pushing my 79 Bronc, 35" with 3.50. Yea I could switch the gears, and yes the 300 is solid but bronco's are heavy and tires in the mud need power. Yea switch it over, as for myself I am installing a 400 (Propane).

The straight six are poor on fuel, had (3) 300-6 motors in different vehicals, 2 Carb and 1 fuel injected.

Good luck!
Ummm....yeah a stock 300 isn't going to do great with 35" tires, but a stock one with stock tires are not by any means poor on fuel. If you're running 35" tires with a 300, and have a non overdrive transmission, you're running around 2500 RPMs the entire time, which is pretty close to pinning in it a 300. That and a 78/79 is HEAVY, they're around 6000 lbs. (I didn't think they put 300s into the 78/79 Broncos). But 80+ are no where near that heavy (mine's 4000). That and most 300 owners get 17+ on the interstate and some get 20+. That's not poor gas mileage, especially when you have V8 guys complaining about 14 with a very very gentle pedal)
But if you're looking for a beast capable of taking the mud on, a V8 is a better choice.

However, from what I gather from you said, a camping, hunting, fishing, farm rig, a 300 is a perfect match and unless you're looking to compete in the mud, a V8 is fun but not truly worth your efforts. A swap is going to cost $$$ and lots of down time collecting extra parts.

As for an EFI 300 with 35", an EFI has around 40 more horsepower than a carbed version so it'll do ok. A couple mods though (much cheaper than a V8 swap) and you won't have any problem with them. Plenty of off-roaders have 35" tires on their stock 300s without a complaint unless they're looking for highway speeds.
The reason I asked if you had an EFI or carbed is because EFI ones take a little more work to mod since you have a computer to work around but with some effort, you can easily compete with the HP and TQ of a stock high output 351.

Don't get me wrong, I love the V8 Broncos and would love to own one and someday I will, but since you are starting with a 300 (especially an EFI one and all the computer systems involved), I'm trying to be very realistic. It is much more worth your time to stick with it and build. The 300s are universally praised and it is a fantastic engine and those that own them swear by them. ;)

My bronco is a manual to which is kinda hard to find a truck that is a manual anymore, at least where i live. thanks for the info.
Which manual do you have? Is it a [[Granny gear + 3 speed]] or a [[3 speed + OverDrive]] ?
 

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I wont contest the 300s rep for unstoppable reliability, but they really arent powerful engines at all. They are perfect for vehicles that arent going to see highway often.

Its going to cost you a whole lot more to get a 300s power numbers on par with a stock 351 than it is to swap the 351. I dont know what part of the swap youthink is so expensive, but as long as you are capable of doing it yourself 302s and 351s are a dime a dozen where im from, as are vehicles with them already in them if you want to pull one that you know is running well. And then you have an already powerful engine with a much more open aftermarket than the 300 ever did.
 

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Trying to finish it
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Discussion Starter · #15 ·
the bronco has 4 gears plus the overdrive that is the 5th gear. and of course the reverse. thanks again guys.
 

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Aheavybronc:

I just built a mild 300 for my Bronco and replaced my dead 351w. There are lots of little parts that had to be changed. I spent a good deal of money making the swap. Now that I have the 300 six back on the road I can tell you that it was worth it. It was a great project and the guys over at the Ford Six Forums (www.fordsix.com) had loads of information.

The 300 mildy built up like I did puts out an estimated 207hp at 4500rpm and 300tq at 2000. I have less than 200 miles on my build so I haven't fully tested it out but I am very happy with my engine.

If you want to get a little more power you can get the later EFI style exhaust manifolds if yours doesn't already have them and change the intake to either a Clifford or an Offy. I went Clifford as it is water heated. You can also change the rocker ratio to 1.75 (currently it'll be 1.6). If you do change the intake you can either go with a 2v or 4v. I went with a small 4v it is a Holly 390cfm. They take a little fiddling to get the secondaries to not kick in early but the small venturis work well on this engine.

Oh, I also have 13.5x35 tires...it's all in the gears. I put in a set of 4.88's with lockers. You can see my engine build at www.morethancarpets-racing.com
 

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Trying to finish it
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Discussion Starter · #17 ·
I am seriously thinking about keeping the 300 and just completely overhauling the engine, which i know is very time consuming and expensive. But, I don't feel like taking my daily driver of the road for that amount of time.

On the other hand I found a 302 for 500$ with 88,000 on it. I figure I can work on the engine while i still can be able to drive my bronco around and on my day off put the finished engine in. Does this sound like a good idea? But the main concern if i do go with this approach will any changes have to be made to the tranny?

Thanks again for your help and info.
 

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I am seriously thinking about keeping the 300 and just completely overhauling the engine, which i know is very time consuming and expensive. But, I don't feel like taking my daily driver of the road for that amount of time.

On the other hand I found a 302 for 500$ with 88,000 on it. I figure I can work on the engine while i still can be able to drive my bronco around and on my day off put the finished engine in. Does this sound like a good idea? But the main concern if i do go with this approach will any changes have to be made to the tranny?

Thanks again for your help and info.
For $500, I'd seriously just go get it and drive it around for a little while and see which one you like more. If you end up liking the 300 more, you can drive the 302 while your 300 is down. If you like the 302, you can either just sell the 300 Bronco, or just figure for $500 you have ALL the parts to do the swap, including the engine.

As far as transmissions go, Ford put the exact same trannies in both the I6 and the V8s. They all bolt up the same except for maybe some very minor parts that just might not be coming to mind right now. But like I said before, some are just better than others. If you have a 5 speed, you most likely have the Mazda transmission. It's not bad and many people like it. However, if you're thinking of doing a swap anyway and want the KING of manual transmissions, find a 4wd ZF-5speed transmission from an F-truck and swap it in.

Either way, if you have the extra $500, go get that 302 Bronco, drive both, see which you like, and choose accordingly. If you like the 300, drive the 302 and sell it for $500 again when the 300 is done! Or if you like the 302, figure you spent $500 for all the parts to do the swap. You really can't go wrong that way.
Of course, then again, it's a lot easier for me to tell you to spend $500 than for you to. ;) But that's what I'd do.

The only thing you might have to consider, (I have no idea of your local laws) is that if you have emissions and they don't allow certain engine swaps. Just something to check into if they do.
 

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Like them tires spinnin'
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For $500, I'd seriously just go get it and drive it around for a little while and see which one you like more. If you end up liking the 300 more, you can drive the 302 while your 300 is down. If you like the 302, you can either just sell the 300 Bronco, or just figure for $500 you have ALL the parts to do the swap, including the engine.
I'm pretty sure he just talking about finding an engine(the 302) itself for $500 not a whole Bronco.

Someday I want to put a souped up 300 six in another truck and cruise it.
 

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A 300 with the right gears will out climb any V8 garunteed. especially in 4 lo. IN 4LO I spend more time on the brake then I do on the gas.

SIXES RULE!!!!!
 
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