what engine should i get?

Question

i am sorta conerned with gas mileage and i was wondering if i should buy a 318 chrysler engine or a 360/300 hp mopar crate. i want the 360 but i dont know how much mileage it will get. also is there a crate 318 i can buy that comes completed?

its going in a 1971 dodge demon and there is a 225 slant six in it right now

Answer 1

Not sure what kind of car or model you are putting the mopar into, but there are several things to think about. Weight of the car, rear gear and transmission. For the most milage out of any engine is to have an overdrive transmission.
Fuel injection is the way to go with any engine set up, getting one to fit is a differant story. Holley has had a TBI with 2 or 4 injectors for several years now but it is pricey, but needs no wiring harness or computer ECU it has its own, replaces a 2 barrel or 4 barrel carb. All you need is the 2 or 4 barrel intake manifold.
When thinking that the smaller engine will be better on gas, this isn't always the correct answer. Just like back in 68 Mustang, you could get a 289ci. or a 428ci. Around town the 289ci. would be better on gas, but in interstate the 428 would almost double the 289.
Either way your driving style is gonna have alot to do with the actual milage you get in the end. If you have the tendancy to put your foot in the "Goat's" ****, then you will most likely do it with a high performance engine or if you get a 318/230hp. I would think you would be more happy with a higher performance engine, sounds good even when it is idling around town.
One thing to think about also, not having experience with the mopar engines myself, I know Ford back in the 70's had a bad problem with all their engines spark knocking, almost any engine they had did such, 302, 351W, 351M, 400M, I read it was mostly due to head design and lower octane gas, they had just regulated down to 87 when the trouble started. My point is if you do a 318ci then you most definatly have to freshen the heads to make sure it is going to run effeciant, the 360 crate is going to be machined up to date and run effeciantly out of the box.

Answer 2

I love reading answers like these when the question is so broad and vague it's meaningless!! I especially like the one where diesel is better for the environment? Why? The first thing you have to consider if you are comparing like vehicles with different engines. Diesel vs Petrol (gasoline for the Yanks!!). If all things are equal, then you look at maintenance and repair, torque, economy - and not in mpg but as a cost per mile due to differences in the costs of fuel. If you need performance, then look at acceleration and hp stats as well as torque. If you are hauling a large boat all the time, torque becomes more important. Then you look at what the engines have on them to get usable numbers. Does it take twin turbos or a supercharger to get the performance gains for the vehicle type for a comparable vehicle with the alternate engine? Those add maintenance issues and possible increased repair costs. The reality is it's about what you feel comfortable with and what makes the most sense for you. Since I know that there are diesel engines in many smaller vehicles in Europe, a Ford Ranger with a diesel is pretty cool. There isn't any one is better than the other, they both have assets and liabilities.

Answer 3

You should be prepared, if you change to a v8 as you suggest, it will be more than the engine you have to change. The engine stanchions on the k-frame for example are different, as is the bell housing pattern, causing the need change the transmissions, even if it is a standard since the trans is altogether different for a slant 6. The radiator is smaller and will not cool the v8 properly.
These are just a few of the things you will run into, but if you are determined to do it, then go with the 340CID. It is a good performance engine that gets fairly decent mpg, if you keep your foot out of it.

Answer 4

If you are worried about mileage then put in the 318. If it's power you are looking for then the 360.

Wait a minute, quit messing around and get a crate 426 hemi and be done with it. lol.

Answer 5

Go with the 360 ci engine. The difference in the gas mileage isn't all that much of a difference.

With the torque and horsepower you get from the 360 you will be happier in the long run especially if you tow something.

Answer 6

What is it going in and what was there before. A 2bbl 318 is a great motor for many years--what would a 360 do? Nothing you would notice.

Answer 7

Leave the "slant" six in it, those things run forever, plus original cars are cooler. How about a Cummins diesel?