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Discussion Starter #1
I have a 78 with the original 400 and C6, and although the motor is still running I've decided to swap in a more modern drive train.

If you had the option of 4bt cummins or 5.0 Coyote or another motor which would you recommend?

Thanks!
 

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I tossed around the coyote for a while in my 92. I decided there was just not enough torque for this size truck. Aditionally the cost of a coyote swap is very high. I'm going 408 with modern sequential fuel injection. 7.3 crossed my mind but the noise and the smell with the top off were drawbacks. I don't know anything about the Cummins. In can imagine it would give you the grunt needed to move that beast.

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1978 Bronco Ranger XLT, 12V P-Pump Cummins, ZF5, Dana 60 Front, Sterling 10.25 Rear
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I’m putting a 6BT in mine. So obviously I’m a bit partial to the 4BT. Just a lot simpler of a swap I’d imagine. Plus like mentioned about the torque on the 4BT is much more fitting to the Bronco. What are you going to be using it for is the real question imo.


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Discussion Starter #4
I’m putting a 6BT in mine. So obviously I’m a bit partial to the 4BT. Just a lot simpler of a swap I’d imagine. Plus like mentioned about the torque on the 4BT is much more fitting to the Bronco. What are you going to be using it for is the real question imo.


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It won't be my daily driver, however I would like to drive it occasionally as I need including in the Canadian winters. As well as do some light offroading.
 

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Coyote would be my choice, assuming you also swap in the matching automatic or 6 spd with gearing to work with where it makes its power. I would urge you to go drive a newer 5.0 f-150 to help make your decision.
My dream truck at the moment would be a new 7.3 gasser powered rig, or even a bit older 6.2L gasser would be just fine too, or a 5.0 coyote with a VMP blower (roots type) torque is a non issue
 
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Purely speculation on my part as I've never been around one but going off the numbers a 4bt doesn't seem like it would be a big enough difference from the 400 to justify the time and costs when a stock 400 can be woken up significantly with an intake, 4bbl carb, cam, and headers. You'll definitely get better mileage than the 400 but gotta determine if it's worth it for your use-case.

I am biased though.. I just installed a reman 400 with an rv cam and all of the smog stuff for CA in my daily driver and I've been enjoying it immensely compared to the 351m with all the above mentioned bolt-ons. A smog-legal LS or Coyote swap is on the list for far-future plans but it's going to be real hard to justify when this 400 is doing it's job for $2200. If it weren't for smog I would have gone with a stroked 460 without hesitation.
 

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Discussion Starter #7
Purely speculation on my part as I've never been around one but going off the numbers a 4bt doesn't seem like it would be a big enough difference from the 400 to justify the time and costs when a stock 400 can be woken up significantly with an intake, 4bbl carb, cam, and headers. You'll definitely get better mileage than the 400 but gotta determine if it's worth it for your use-case.

I am biased though.. I just installed a reman 400 with an rv cam and all of the smog stuff for CA in my daily driver and I've been enjoying it immensely compared to the 351m with all the above mentioned bolt-ons. A smog-legal LS or Coyote swap is on the list for far-future plans but it's going to be real hard to justify when this 400 is doing it's job for $2200. If it weren't for smog I would have gone with a stroked 460 without hesitation.
You make a good point, one of the main reasons for swapping is reliability especially in the Canadian winters. I know I could rebuild the 400 and put an EFI on it, but after spending all that it might be more worthwhile to get the coyote with the extra power and fuel economy that goes along with it.
 

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You need to dig into the cost of a coyote swap. When I did it just didn't make financial sense. The few miles per gallon you would gain wouldn't pay you back for years. Cool factor would be high though. Rebuilding what you have and adding fuel injection would be a real nice driver for significantly cheaper. Google coyote swap cost. If you do do the coyote make sure you post your build. I will follow. Just my 2 cents or 4 cents I guess.

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@SHOme are you looking at a 408w? What fuel injection setup are you thinking about? I have a 351w shortblock waiting on some heads, and have considered mating it to a 6r80 to go in my bronco.
 

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Yes. Block is at machine shop now. I'm planning on a Megasquirt. I picked up a Ron Francis harness and the MSD dual output distributor that will give me a crank sensor for sequential. I basically am following Seattle FSB engine parts minus forged. I have the 6R80 and adapter. Currently I'm stripping the frame trying to get everything cleaned up and painted. You might want to follow my build unless you will have yours done in the next year😁92 stroker
 

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85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
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For hopping up the 400, check out TMeyer. He is the "M" block guru. Okay/decent mpgs.

For a good driver, with great offroad manners, the 4bt is a great choice. Good mpgs. Though a 7.3 powerstroke would be my diesel swap of choice. I cant get enough of that international cackle!

For a good driver that you can roast the tires with, a coyote will be best. Decent mpgs.

I think a 460 would be worth looking into. Better yet, an efi 460. Plus it bolts up to your transmission. Good power and torque but just okay mpgs.

One aspect of an engine swap and mpgs, is that it is inevitable that you wont be harder on the throttle than before. Initial mpgs will suffer, but once you get used to it, maybe, they will improve
 

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With reliability being a priority I don't see what's wrong with a 400 and a carburetor... easy to work on, easy to hack/limp home if it ever breaks/causes issues, parts are cheap, and that mill will put up with A LOT of abuse before it gives up. Power is easy to get out of them (see TMeyer as mentioned above). I would love a 460 (smog laws stop me here) but I'd only go through the trouble if I was stroking it out and going big, otherwise the 400 is fully capable of putting a smile on your face.
 
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