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?