How gutless and manifold exchange...?

[mmwb]

My 76 m880 idles nicely (purrs like a kitten) and seems consistent at varying speeds, but it is rather gutless. I realize these things were never power horses from the factory, but it seems to me that the 318 should put a bit more umph out... My 90 k1500 and 96 f150 both totally put this beast to shame.

A friend has the intake and a large 2bbl Holly carb (I can't find a number on it) off of a 360. He said it was torquey as all get out at the lower end, but weak at the top end. I'm wondering if this would be a worthwhile addition. I need enough low end so that I know I can push snow with this thing.

As I am just getting this thing going, I've still a lot of possibilities to work on. It has had an electronic ignition added at some time. I've not checked compression or timing. I also have yet to tune the current Carter 2bbl...

Any input would be appreciated.

 

[WillWagner]

I had a '77 1/2 ton power wagon. It was a gutless pig. I went to the bone yard and picked up a stock,4 bbl manifold and an AFB carb. It made it come alive but the mileage suffered. Did I mention it had 38s on it? I dropped them down to 33', but it was still a gas hog.

 

[Blood_of_Tyrants]

Chrysler's 318 was a pretty well thought out motor. It does well with a stock 2 barrel carb and manifold. Check your timing and compression and make sure your air filter isn't clogged.

 

[No.2Diesel]

Get an Edelbrock Performer Intake Manifold, a Holley 4175 (similar to a the Thermoquad spread bore, small primaries, large vacuum secondaries) and run full length headers with a dual exhaust with a balance tube. If you want a small (very small) increase in compression ratio you can get a thinner head gasket.

A propery selected 4barrel will always get better MPG and throttle response then a large 2barrel.

 

[pa.rich]

They are gas hogs but the 68 power wagon we used at work was gutsy. 6-8 mpg.

 

[M543A2]

I agree with No2Diesel's comments. The biggest problem I have with the military 318's is the low compression ratio. We have a '85 318 in a pickup and it responds entirely differently.
I will have to say though that I am going to take out my 318 and put in a 383, 400, 413, or 440 depending which i pull out of our spare engine shed. We have consistently been able to get better fuel mileage from these "B" and "RB" series Mopar motors than the "A" series motors, even at larger displacements. They warm up quicker and make more power, and are easier to work on. You can even change the oil pumps without dropping the pan. Like your manifold change. You are dealing with the same stuff you have to with a Chevy motor; all of the water passages in the manifold and distributor removal. The seals at the ends of the 318 intake are always a problem sometime down the line. The B series motors have manifolds that can be changed with no water or distributor involved. The front distributor is nice, too. The biggest problem is you have to change the transmission housing to get the right bolt pattern to fit the B and RB motors. Sorry; I digressed here. You do not want to get into all of that work unless you are lucky enough to have the parts on hand.
A mild cam would be a nice addition with the 4 barrel and headers. A four barrel with the smaller primaries is more responsive, and fuel mileage is controlled by your foot on the pedal not going into the other barrels unless you really need it.
Regards Marti

 

[McGuyver]

`77 was the worst affected year for the 318 as a resulty of the EPA regulations of the `70's. The lower compression ratio ( required due to the elimination of leaded gas) dropped the horsepower of these motors down to 150 hp by 1977 (contrast this with what they were putting out in the early `70's at over 200 hp)

If you wanted to rebuild this motor with a higher compression ratio, and run higher octane unleaded fuel (which I don't think was really availaby yet in `77), you may be able to get some of that power back up.

 

[tractorfix]

The only way you use the 360 intake is if you also use 360 heads. The 360 intake has larger ports that when put against the small ports of the 318 head makes the engine inefficient. The thing that really screws up the M880 is the 4.10 gear and lack of overdrive. The Ford and Chev mentioned above both have injected motors, 4spd trannies and reasonable gears.

 

[Bob H]

Lots of good points.
The valves are tiny, the ports are small.
Simply putting a 4 barrel on won't help.
For power, you'll need the 360 heads with small combustion chambers, or heads from a 85 / 86 5.2 Police car motor (bigger valves!)

Ok yea pretty gutless, but with the 4.10 gears they will move quite a bit. Just not real fast.
Just last spring I hauled a 6100 lb ambulance on an 1800 lb trailer plus an assortment of parts in the bed of the truck along with a few hundred pounds of tools & equipment. @ 60-65 and got better than 10 mpg doin it. and my 318 is bone stock!