Sweptline.ORG

would it be a bolt in swap? 67 d200 long bed with granny low np435.Dana 60 4.10's I'm also taking offers on it I figured if the swap isn't realistic I will let her go to a good home. it's my daily driver, 60 miles a day 5 days a week. Drive train is great but the cost of fuel doesn't allow me to give it the love it needs I will send pics if interested. Thanks guys

I hate to discourage you, but I don't think that going to a slant six will help your milage. In fact, it may be worse. The six will be working harder to do the same job.

Maybe a smaller carb or jet something? I have heard that a 4 barrel with smaller jets can get better mileage than a 2 barrel but Ive never confirmed that.

My 2 barrel 318 seems to get the same mileage as my 4 barrel stroked 360, so maybe its true.

what about adding a fuel injection system to your v-8?

Roughly half of a vehicle's energy is used to over come air resistance and the other half is used for acceleration. Make it lighter, lower, narrower tires and an engine big enough that it doesn't have to work hard to move the truck. Also some engine tweaking and monitoring driving habits may help. There isn't really much you can do to improve the aerodynamics of a sweptline.

Before you make any major changes determine if they are going to cost you more than any benefits you will see in fuel consumption. A lot of changes usually aren't worth it when you figure the costs involved unless the price of fuel keeps rising.

from everything i have heard , the /6 is your best bet for fuel millage . v-8 have 2 more cylinders to fill with gas...get your slant tuned up.. go too slant 6 web. they are great for info ...
I personally use a Gold Wing for fuel millage ..or a cheep... gas get-r car
Larry b

There are two variables here, the amount of horsepower you are actually going to use, and the specific fuel consumption, that is, the pounds of fuel per horsepower per hour your engine consumes.

Putting in a slant six won't reduce the amount of horsepower you need to do a given job of driving your truck. Since the slanty is heavier than the LA engine, it might even take a little more horsepower. What would reduce the horsepower/hours you need is to reduce the truck's rolling resistance (tires), its aerodynamic drag (a camper shell here could help), and to learn to drive the truck to use less power and conserve what is there. That is the secret of the old "Economy Runs" where they could drive with twice the normal mileage. There are books on this and you could get one from the library, maybe on interlibrary loan.

One aid is to put in a manifold pressure gauge and learn to use it. You want one calibrated to read true MAP, that is, it reads 29.92 when the engine is off and 10-13 at idle. The car gauge companies refuse to make these because they are convinced anyone buying one will put it in a homebuilt airplane and the lawyers have terrorized them.

Improving specific fuel consumption is possible. Here too, a slanty is not going to be a big help. They are old tech engines, just like your 318.

The Big Fix here would be to go to a turbocharged diesel. Diesels get substantially better sfc figures than do gas engines because the Diesel cycle more closely approximates the Carnot cycle of theoretical efficiency than the Otto cycle engine does. There are diesels that would fit your truck, but unless you get really lucky and find a cheap surplus overhauled SD33T Nissan you are going to spend a big pile of money to do it. You can buy a lot of gas for the price of a diesel engine, plus the beefing-up of the front end any other diesel of sufficient performance (except a four cylinder Isuzu or a OM617 Mercedes) will take. I did the plumbing and wiring on a Detroit Diesel conversion in a Suburban. The plumbing and wiring was easy. The rework of the front end-for a 1100 pound engine-was expensive. (Free jet fuel was a big motivator.)

Short of that, improving your 318 by optimizing its induction and ignition, and making sure you have suitable gearing is going to bring the most results. Swapping a 318 Magnum fuel injected engine with all its electronics and the overdrive 4 speed automatic that comes with it or a 5 or 6 speed manual will definitely up your mileage, and cheaper than a diesel, but again you can buy a lot of gas....The driveability will be great though.

Do you drive your truck every day? is a truck what you NEED? I bet the real answer is to drive the truck when you need a truck and spend a couple grand on a used, still running good front wheel drive EFI grocery getter for everyday use. At $3.50 a gallon it will pay itself off in a year or so.

I have five old cars and trucks and two bikes. I drive a '99 H***a to work most days of the week. It cost me $1500 and it's the best old car maintenance tool I own.