What engines fit in my 79' B300

Hi all,
I'm back...

I'm not having any issues with my van I'm just curious to know what motors will fit in my 79' Dodge B300 extended cargo van??

I have the LA360 that was rebuilt before I purchased it. Had some issues but all is fixed and running great! I haven't driven it enough since the carb rebuild and tranny rebuild to know if that work has helped get me better mpg's but I would assume it's still around 10mpg...

So I've been entertaining the idea of swapping my 360 for something that gets better gas mileage...

Will a 318 of the appropriate year have the correct configuration of the mounts and will bolt to the tranny without an adapter??

What engines that get better mpg's will fit in my van without adapters or modification??

Generally speaking, it takes a certain amount of power to move a vehicle. The bigger and less aerodynamic the more power is needed. you may very well find that a smaller engine gets worse mileage as it has to work harder to make the power. In a B300 I wouldn't think a 318 would be a better choice. In 78, same ride essentially, Chrysler put the 225, 318, 360, 400 and 440 in them. I imagine any of those would "fit". If I were looking to do a swap I'd think hard about a 400 but mostly I would just optimize the 360.

Would be better off keeping the great running 360 and work towards an overdrive setup with 3.55 gear out back.

I guess a stroker version of the LA360 would bolt right up and give you more power all around. Probably won't help the gas mileage, though....

I have a 2002 Dodge Ram Van with 5.9 and overdrive. It is a hightop conversion. It gets 11 mpg. Period. In town, interstate, towing a small trailer, etc. It has the aerodynamics of a brick and fuel mileage is limited by that. Tune the engine you have rather than worrying about a swap.

I had a 79 B200 shorty van with a 318/833OD and 3.55 gears and it got 25mpg hwy all day long here in Colorado.
Also a 91 B300 with 360/518 and 3.55 and it got 21mpg.

You should be getting better than that even with the hightop.

FWIW, my FIL had a 1980 Ford van, 460 powered, if my Dad drove it, 10 MPG, if I drove it, I'd get near 12 MPG, highway. We described as being like pushing two 4'x8's into the wind. My MIL had a 1985 Dodge shortie with a slant six, it didn't do much better and was slower than Christmas. Need good gas mileage? Drive something else.

Almost forgot, my little sister had a '96 Dodge shortie conversion van, magnum V6, three speed auto, 16 MPG highway. Faster than the 1985, still needed a calendar for 0-60...

I wouldn't expect more than 12mpg out of a 460.

Best I got from my 79 B300 maxi, 360 4 bbl, raised camper roof was ~11 mpg (CDN). Have a 79 motor home with a 440, and the doghouse is wider on the pass side. If you put in a big block, you would need the larger cover. Thought of a 518 swap, lots of room underneath, but its got the rust worm bad.

Unless you drive it a lot it will take a lot of gas saving to cover the cost of a motor or trans swap. Use the money to buy a little car and use the van when you need a van.

This one is the winner.

Swapping motors or transmissions just to save money on fuel mileage is a vain effort. Even if you could increase your mileage by 4-5 more mpg (which is pretty questionable in my opinion, 1 or 2 mpg improvement is probably more realistic), at $5 a gallon gas, how many miles do you have to drive to break even with the cost of whatever you swapped in? Will you drive it enough miles to make it worth the effort?

Yeah I get it, makes sense especially with an extended van and bigger than stock tires I recently installed...
I have thought about replacing the intake but what sort of optimizations can I make for the van to be more efficient??

That's pretty much what I've been doing. I have a 2000 S10 truck that's my daily driver...
Here's the thing, I live in a rural area on a Ranch, it's basically an off-grid community and the county doesn't come back here. I'm thinking of using the van to start a business and provide some sort of service out here but I'm not sure what... Trash pickup, water delivery, basic home maintenance etc... I'd like to be able to squeeze out as many mpg's out of it to make my business more profitable.
I can't make much money if most of my earnings go to fuel costs... For example, it's about 70 miles round trip when I go into town...
In general it'd be nice to get more mpg's but not if I'm going to spend more on a swap than I would paying for gas...

As mentioned before in one of my other threads, I have a 94' B250 that's basically a parts van at this point. It has a 4speed auto A518 tranny and apparently it'll be possible to swap the tranny and get better mpg's but I just rebuilt the tranny in my B300!

Ok, say I optimize the 360 and rebuild the tranny out of the 250. What optimizations can I make to the engine and what mods are necessary to install the tranny from the 250??

Would it really be worth all the work to swap tranny's though? How many more mpg's can I get with the tranny from the 250?
I think maybe fixing up the 360 will be the most viable option considering all the comments...

For now, I guess I'll just focus on what can be done with the 360 to make it more efficient...
Apparently my van has or had the ability to run on propane?? There's a sticker under the hood that mentions the fuel mixture process for propane in that motor...
Any thoughts on this?

I get it but where I live squeezing as many mpg's out of it would be worth it. It's 70 miles round trip when I go to the store! As for spending money on a motor or trans, I already have a 4 speed auto A518 out of the 94'... I'd only spend money on a rebuild kit and whatever else needs to be done. Not sure the condition of it, I towed it home...

Right now I would realistically only be able to fix up the 360 to make it more efficient... What does that entail and will it be worth it? I can imagine I can spend anywhere from $200 to $2000 just to modify the motor.
The whole point of all of this is to save money...

I expect someone to tell me that I should probably sell it and get a different.vehicle but right now I'm just too attached to the van since I've done so much work on it... I've had it for at least 8 years, lived in it for a while... I want to make it work for me!

i can't remember what you said your van had for a carb, but if it's a 2bbl, swapping over to a 4bbl manifold and running the small T-quad should yield a couple mpgs.
however, you will need to learn how to tune the T-quad, and realize jets and metering rods are semi-hard to come by and may be a little expensive.

Honestly, with the stuff you have already done, you may have gained about all you will get out of your van. You probably need to get it going and drive it a few months and get real gas mileage numbers.

You may gain better gas mileage by changing how you drive the van. I can get 2-3 mpg better mileage then my wife driving the same vehicle, she has a bigger lead foot then I do, and I don't drive for the best gas mileage. Want better gas mileage? Don't drive like I do.

The best investment you may make for getting better gas mileage is to buy and install a vacuum gauge, and never let the needle drop below 15 while your driving. Your van will probably get the best gas mileage at 55 mph, or maybe 60, or maybe 50! Any speed above that reduces the gas mileage most of the time, you have to find the speed the van likes to run. Driving for the best gas mileage is a learned art, and you have to be 100% dedicated to it, one slip up can kill the mileage for the whole tank full. Gene

Tuning the carb and timing might add a bit, but generally trying to eek out a few more MPG on a 1 ton van is a search for minimal gains.

It's the 2210 and if it matters, the intake is the style with all the smog stuff... Not sure if I wanna go the route where I'll have trouble finding parts though...

I think you may be right... I still need to take my van for a drive to get a real sense of it's fuel usage... I've only been doing circles on my property... The last time I took it on a drive was when the shaft fell off on the freeway and then wouldnt start up and had to get it towed...

I use to get up to 10 mpg and after everything I've done with the carb and tranny I would expect at least a 1mpg increase! The carb had no check weight and larger jets, since then I replaced the jet's with smaller ones and the check weight has a large role to play in fuel usage I would assume...
Is the assumption that having the check weight in the carb saves more gas than not having it correct?

For now I think I've done all the tuning I can do, it's just a matter of going on a drive and putting it to the test... I'm just a little hesitant since the last time I drove it was when it broke on me on the freeway... I'm trying to make sure I've done everything I can to prevent another break down... Living where I do it's not like I can get towed home either. I'm about 4 miles off the freeway on a dirt road and tow companies generally don't drive out here!

Would love to know how that happens, my 02 gets 14.5 on a good day. I bought a 92 250 extended people van for the 360 518 to put in my LilRed but I might just stick the whole package in the 88 long bed 318 904 if I can get that kind of millage.

Those 20 something mpg numbers were all rolling down hill in Colorado. No word on the uphill mileage.

The best gas mileage I've ever gotten out of a Dodge truck, or van was from the V6 mini van years ago (which was nearly always near 20 mpg), and my current truck.
Last year my truck went from home here to the west side of St Louis (365 miles each way) The truck got 17.3 mpg on both the trip down, and the trip back up, and 14.6 while there (2 days). The sheet metal is sitting on a 96 Dakota 4x4 chassis with an EFI 318, and the OD auto trans, and 3:55 gears. The mileage on the interstate through Iowa was on the Mopar factory cruise control set at 72 mph. The gas stop on both directions was made at nearly the same mileage, from the same gas station. The truck was filled up 2 blocks from home, and the return trip was filled up 2 miles from the hotel we stayed at. All the gas stops were at the very same gas stations, and the mileage was recorded by the trucks odometer. The cruise speed matched the GPS speed. No bs here.

Pictures of the truck, probably the day before it went on the trip to ST Louis. Its a 49 Dodge pickup on a 96 Dakota 4x4 frame (yes, the 4x4 functions). The frame was unaltered except for the shortening of the wheel base by about 8" and uses all the Dakota mounting brackets, drive train, fuel tank, wiring and computer. Gene

Don't you know there is only one engine that can be used today, that is the LS...

That is a nice looking truck Gene. I had a 92 Dakota ext cab long bed 5.2 518 3.55 gear that would knock down 20mpg on the interstate. Tonneau cover, electric fan, and taller tires helped up the mileage a bit.

Last November going to Savanna from Va I got 19.7 from my 06 3500 4x4 diesel @ 70-75 mph down ins 95, my 92 4x4 2500 diesel got a best of 23.5 on ins 81 going to Carlisle and back. Just can’t get the gasser that good.

The easier and cheaper MPG improvers are
aerodynamic mods
low rolling resistance tires.

aero tweaks to try are
larger front air dams made of easy to replace materials if they hit something
vortex generators like “shark fins”, homemade wheeler vortex generators or commercial 18 wheel truck “air tabs”
rear wheel skirts

after lowering engine rpm at cruise highway speed,
the next bigger MPG gains come from
raising air to fuel ratio from 14.7 up to the range of 16 to 25

non-USA versions of the early years Honda Insight engine would raise air to fuel ratio at highway cruise to 25

It is the USA NOx emissions rule that keeps air to fuel ratio to 14.7
The NOx regs kill best possible fuel economy, and therefore greatly raise emissions of CO2

Thanks. Future improvements will be coming next spring. A bed cover is high on the list, it looks like it will need to be custom made. This truck has a pretty aggressive tread pattern 235/75/R15 tires on it, it is used as a 4x4 being driven through the winter. It does haul stuff and is a work truck. Gas mileage was not ever the highest priority with me, I have too heavy of a foot. Honestly, I was pleasantly surprised with the 17 + mpg at 70 mph. In town and winter short trip driving nets a pretty much expected 10 mpg range. Gene

Those windows in a compact cabin sure seem to give great 360 degree visibility compared to modern pickups.

The windows provide a better view then my old neck can twist to see! The only blind spots on this truck is what the mirrors block, and they are pretty small and easy to look around. Now, if the seat would go back another 2", or my belly was 2" less around, or I don't have to have that bulky winter coat on, it is a very comfortable truck to drive. Has heat, an awesome defroster, and a functioning outside vent for the hotter weather, might even get AC for the summer.

My wife and I went for a ride today, full sun and upper 30s temps, I was able to drive without my coat on very nice and relaxing! At 55-60 on the cruise, 122 miles used right at 1/2 a tank (according to the gauge), less fuel then the 60 I put on the last tank full that got 9.9 mpg (warm up idle time and around town), but I did not refill, so take that as it is.

I bought the 49 sheet metal and it's original twisted frame, and a Dakota rolling 4x4 frame in 2019. It sat until I started taking apart the donor Dakota in mid July, 2020, and then started on the 49. I plated this truck in June 2022. It has about 4,000 miles on it since its been plated. Body work starts this spring, and it will hopefully be painted by fall. Not going to be a show truck, just a good looking work/driver. It is my winter transportation.
I should probably start a thread for my truck rather then messing up this one. Gene

Gene, as to getting the seat back a couple of inches.
since you have the gas tank in the dakota location, and out of the cab, is there a couple of stiffening ribs on the back of the cab wall you could remove, allowing the seat to touch the back of the cab ?
just thinking out loud here, as i am not familiar with those year trucks.
or maybe you have already done that, and i either forgot about it, or missed it when you said you did that.

Remember what goes up must come down. Maybe only get 10 going up but get 30 downing down. Also that is empty with no headwind.
I'm lucky to get 19-20 out of my 5.2 Dakotas but they are heavy little pigs.

The top of the seats are under the back window supports. I can back the seat bottom up a bit more, but then the seat sits more upright and is a lot less comfortable. With my thick winter coat on, the wheel is very close to the coat, I have to suck it in to get the seat belt between the coat and the wheel. Its more of a fat old man problem. The truck also has a tilt column. If the column was a bit shorter, the issue would be gone, but then I'd have to change a bunch of other stuff. I'll just deal with it the way it is during the winter, without the heavy winter coat, there is not a problem. I would guess this old age thing is making me pretty picky, it wouldn't have bothered me in my younger years.

So should I put a build tread in the truck section, or the street rod section?

I agree with those suggesting tuning what you've got. Optimizing timing and both advance curves. What gear is in the rear?
What size tires? The basics are trying to reduce the size you're pushing into the wind, in my experience this is mostly helpful at highway cruise speed.
Narrower tires with higher air pressure, especially if you've already got some to try.
Rig up a front air dam to reduce airflow under the van.
Close off as many holes in the grille that aren't needed for engine cooling, same for your cowl louvers.
Run smaller outside mirrors, even try folding your pass side mirror, or remove it.
Can probably lower the front by cutting coils, not sure if your leaves are under the rear axle, or over.
If under, lowering blocks and longer U-bolts will do the job.
I'd look into swapping the trans, especially if you've got all the parts needed..
But again, these changes will mainly pay off at higher speeds.
A four barrel swap, and a lower rear end gear ratio would also help.
Tuning parts for the popular 4V carbs should be easier to find than for your 2V carb.
I'm assuming you're running the stock 360 2V camshaft, if so, I wouldn't change it.

I would move the whole column farther down into the firewall. Or flat steering wheel

"So should I put a build tread in the truck section, or the street rod section?"


myself would suggest the street rod forum. maybe both if it's allowed ?
i see what you mean about moving the rear cushion backward.
however if the top of the seat is now touching the brace that runs from the rear window to the floor [that was possibly for the gas tank ?], taking that brace out would allow the seat back to go maybe another inch or so rearward, still allowing the back angle that is comfortable for you.
just my thought from far, far, away. it may be entirely different seeing it in person.


now back to our originally scheduled program..................

Yeah, you can use the van for any use for starting a business. I really appreciate your idea to start a business and if you are starting then you need to go through the secretary of state texas business entity search to smoothly create your own business in texas. If you creating an LLC use for your business use a van then it will fall under the property a van.