Torque + Fuel economy

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Jonnylightening

Jonnylightening

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Hey guys working on my d150 for winter/work. Wondering what are some good parts choices to get the most torque/fuel economy. It's the 225 with 904
 
Mill the head to get about 8.5-8.8 compression ratio (measured true). 2 1/4 inch exhaust system, 2 bbl carb. Maybe a mild torque cam. This is assuming you are still going to use it as a truck. Another possible upgrade, depending on the year, would be a "lockup" 904 trans.
 
Headers, weber progressive carb.
Msd ignition, timing curve setup.
Good wheel and belt alignment.
Skinny tires.
Aluminum intake for weight reduction.
 
I have an 84 D150 with a 318.There ain't much I could do with it; there is just too much frontal area.
HI- Compression, hi-way gears, lower it, pump the tire pressure to the top, and drive that brick slower.
 
Both goals torque and mpg are waste of money chasing. NA Torque is mainly dependent on displacement most stock to mild engines will produce 1 to about 1.15 lbs-ft per cid. More CR good exhaust, less restrictive intake side etc.., maybe a mild cam.

Fuel mileage is hard to recoup unless your spending crazy amounts in gas a years, if you spent $2500-5000 a year and increased mileage by 10% would be a $250-500 savings which you could easily spend multiples of that chasing mileage other than basic tune and setup.

usually cheaper to dump the money into the tank when doing anything above the basics.
 
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Just tune it up good and enjoy it. You mill the head and headers and cam and all that you will be disappointed. I would do a v8 swap before modding up the slant, they are just too wimpy to push that big *** truck around. A 318 will have more power and get the same mileage, maybe better mileage, depending how you are driving it.
 
I Agree with what has been said RV torque Camshaft, 2 Barrel carb, Headers,Head mill,electric fans or a fan clutch, MSD Box, A good distributor curve and alot a V-CAN, an open air cleaner, also getting rid of extra weight like AC compressor and condensers unless you use them.
 
another guy with a slant powered D150. Not my 1st. Back when I had the 1st one, I did the 318 swap..... this time I am going to see what I can get the slant to do..... My son also has a slant powered truck.... a good tuneup, replaced the melted out 4 pin ECU (ignition box) with a good quality new aftermarket one from "back in the day" (we found an old Niehoff box that was at least 35 years old but brand new in the box) Super 6'd it with an NOS BBD, and just played with it to get it "the best it could be" for now..... head will probably come off for a shave and possibly mild porting, eventually. but even without that it runs much much better than when he got it.

On mine (actually has a 727 not a 904 to begin with) I happened upon another slant.... I figure I have a fighting chance to get a decent running truck that will get out of its own way by instead of having to buy a V8 trans, V8 mounts, V8 exhaust, and depending on the motor I wound up with to swap in, also possibly having to buy V8 pan and V8 mounts..... that gives me "extra money" to see just what I can get out of a slant..... yeah it's a bit doggy at present, but no worse than the 3.9 in my 99 Dakota..... I am rebuilding this other slant, it's in the machine shop right now. It's gettin bored, the head is getting shaved (as soon as I finish the porting job) oversize valves, a reground cam, a Super 6 with an NOS BBD like we put onto the kid's truck, and we will see what that gets me.
 
@my68barracuda
Needs to chime in. He tows his /6 race Barracuda with a slant-powered truck.
Saw his rig at the Clay City /6 Race 2 years ago that he drove from 2 states away.
 
I've had /6s, 318s and 360s over the years that have impressed me, and I have had a few slugs among the bunch. The 360 that was originally in my son's ramcharger was hands down the doggiest 360 I have ever driven. It was a TBI which sucks in itself. But at least the 318 TBI in my old 88 D150 and the 360 TBI in my kid's 90 W250 would get out of their own way.
I've had/6s that scooted along pretty well for such a small CID engine and I have had some duds
 
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The best mod I've done to my 1980 D150 with 225/A727 (w/lockup) is Trailbeast's HEI ignition.
 
DodgeLad said:
The best mod I've done to my 1980 D150 with 225/A727 (w/lockup) is Trailbeast's HEI ignition.
Click to expand...
Well I put an NOS Mopar electronic ignition distributor in my 85 and did away with the lean burn, also a NOS aftermarket 4 pin stock style ignition box, made a big difference.
 
volaredon said:
Well I put an NOS Mopar electronic ignition distributor in my 85 and did away with the lean burn, also a NOS aftermarket 4 pin stock style ignition box, made a big difference.
Click to expand...
I was in favor of eliminating the coil, condenser, resistor and box. I already had a compatible distributor.
Did Magnecor wires, stock wires can't take the HEI jolt. Iridium plugs too. Starts are immediate. Idle is smooth and steady. Runs like a champ, a very low HP champ that is. I was able to leave the stock stuff there too.
 
I had no reason or desire to leave any of the "stock stuff" in place regarding carb or ignition. the only "stock" (original) piece on mine would be the coil. Everything on mine is "stock" but "stock" for at least a 5 year older (or more) truck. Im headed for an engine that is 11 years older than the truck itself, and it will not be stock.... Lots of "stock components" but for various years of teh slant 6, mixed in with a couple of non stock goodies.... mainly the cam and head/ which are stock pieces, but not stock as stock was, when they left the factory. The cam is headed to oregon for a regrind, the head is ported now and will be getting a shave and oversize valves.
add a stock from a different year Super 6 intake, an "opened up" stock exhaust manifold, and a stock for a 318, NOS BBD carb...... so yeah... it will be "mostly stock" when done.
 
Think of it this way;
The stock slanty makes about what? say 85Net horsepower.
And that brick of a truck needs about 45/50 of em to cruise with at 65mph.
If you do the usual hop-ups to it, and gross it up 50%, to 130Net, Now you still got a slug because that truck is not just a brick, but a heavy brick.
Consider that even a stock smog-era 318 makes more than 130hp.
Now consider the cost to bring the slanty up to 130hp, versus just grabbing a JY 318 with attached transmission.

Or better yet, a 5.2M with a loc-up A999/A998 advertised at 230hpNet. These come already with 9.2 Scr IIRC, or more.

Or best of all, a 5.2M with a loc-up A500/A518 and a 3.91 rearend, out of a JY Dakota. Now you got something for not just Torque and Economy, but it also smokes both tires from take-off, and accelerates to 65, quicker than " we'll get there when we get there."

I mean I don't know the cost of that last one, But I sure as heck wouldn't spend an extra nickle on the slanty over a tune up; starting with a compression test.
 
My last slant was an 80's D100...simple tune up and it did 20+ mpg. Just a nice simple $400.00 truck.
 
AJ/FormS said:
Think of it this way;
The stock slanty makes about what? say 85Net horsepower.
And that brick of a truck needs about 45/50 of em to cruise with at 65mph.
If you do the usual hop-ups to it, and gross it up 50%, to 130Net, Now you still got a slug because that truck is not just a brick, but a heavy brick.
Consider that even a stock smog-era 318 makes more than 130hp.
Now consider the cost to bring the slanty up to 130hp, versus just grabbing a JY 318 with attached transmission.

Or better yet, a 5.2M with a loc-up A999/A998 advertised at 230hpNet. These come already with 9.2 Scr IIRC, or more.

Or best of all, a 5.2M with a loc-up A500/A518 and a 3.91 rearend, out of a JY Dakota. Now you got something for not just Torque and Economy, but it also smokes both tires from take-off, and accelerates to 65, quicker than " we'll get there when we get there."

I mean I don't know the cost of that last one, But I sure as heck wouldn't spend an extra nickle on the slanty over a tune up; starting with a compression test.
Click to expand...
The 83 D150 has
.030 os pistons
Holly 2280 carb
Cast Aluminum Mopar Performance intake with hot water heat to the base of the carb and a cold - outside air inlet.
Windage tray
OS valves, mild porting
Head Milled to get 8.5 static compression
Hydraulic Cam 212 and 206 @.050 with 340 valve springs.
HEI ignition, Magnacore wires, performance coil
Curve brings advance in early
Dual Dutras
Free flowing exhaust
Electric radiator fan
Made around 150 hp at the rear wheels on a chassis dyno.
Motors just fine on the highway, all that frontal area kills mileage above 75 mph but not the speed. It will easily run 90+
VolarieDon has seen the 83 D150.

AJ, the stock cam in your lean burn era D truck coupled with its low static compression, and a conservative ignition curve is really restricting that motor. I am not saying that a similar build with a v8 could not do as well.
I am saying it does not take extreme work to get a slant to run well, and when you are done, it’s not just another v8. Either you get that or you don’t.
 
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I just keep my little 170 in top tune and drive the heck out of it.
 
I have two dodge trucks. 1984 D-100 slant six A-833od 3.91 SG rear. When I first got the truck, I towed my race car, from Florida to Clay City Ky. I did absolutly nothing to the truck, except change the oil between getting it and leaving. I got 13 mpg on the trip. I will say the truck has some upgrades by the previous owner. Non lean burn, and a super six intake/carb. I have never checked unloaded mileage, as I don't use it much (the clutch slips under heavy load).
My 88 D150 has a 360 /727 with a Q-jet carb. That truck gets 9-9.5 mpg empty, or pulling a race car.
 
my68barracuda said:
it’s not just another v8. Either you get that or you don’t.
Click to expand...
I do get that.
But that was not the OPs question.
Here is post #1;
Jonnylightening said:
Hey guys working on my d150 for winter/work. Wondering what are some good parts choices to get the most torque/fuel economy. It's the 225 with 904
Click to expand...
And so, I also get that an engine swap was also not in the OPs question. So Ima gonna Zip it, about that. And so, I will just re-iterate post #4;
AJ/FormS said:
I have an 84 D150 with a 318.There ain't much I could do with it; there is just too much frontal area.
HI- Compression, hi-way gears, lower it, pump the tire pressure to the top, and drive that brick slower.
Click to expand...

To which I will add ;
273 said:
Both goals torque and mpg are waste of money chasing. NA Torque is mainly dependent on displacement most stock to mild engines will produce 1 to about 1.15 lbs-ft per cid. More CR good exhaust, less restrictive intake side etc.., maybe a mild cam.

Fuel mileage is hard to recoup unless your spending crazy amounts in gas a years, if you spent $2500-5000 a year and increased mileage by 10% would be a $250-500 savings which you could easily spend multiples of that chasing mileage other than basic tune and setup.

usually cheaper to dump the money into the tank when doing anything above the basics.[/QUOTE]
Click to expand...
 
my68barracuda said:
The 83 D150 has
.030 os pistons
Holly 2280 carb
Cast Aluminum Mopar Performance intake with hot water heat to the base of the carb and a cold - outside air inlet.
Windage tray
OS valves, mild porting
Head Milled to get 8.5 static compression
Hydraulic Cam 212 and 206 @.050 with 340 valve springs.
HEI ignition, Magnacore wires, performance coil
Curve brings advance in early
Dual Dutras
Free flowing exhaust
Electric radiator fan
Made around 150 hp at the rear wheels on a chassis dyno.
Motors just fine on the highway, all that frontal area kills mileage above 75 mph but not the speed. It will easily run 90+
VolarieDon has seen the 83 D150.

AJ, the stock cam in your lean burn era D truck coupled with its low static compression, and a conservative ignition curve is really restricting that motor. I am not saying that a similar build with a v8 could not do as well.
I am saying it does not take extreme work to get a slant to run well, and when you are done, it’s not just another v8. Either you get that or you don’t.
Click to expand...
any idea where one can obtain a slant 6 windage tray?
 
DodgeLad said:
The best mod I've done to my 1980 D150 with 225/A727 (w/lockup) is Trailbeast's HEI ignition.
Click to expand...

Who is trail beast?

Also someone said something about displacement pretty well being mandatory for torque. That is only part of the picture. Even if you have a 440, compression ratio, breathing and more goes into it than just sheer CID. As compared to similar displacement engines from any brand, the long stroke of a slant gives it a huge advantage over other engines.
Look at a 300-6 vs a 302 ford in a truck. The 300 was rated for more towing capacity even though it is 2 cylinders less. The combo of bore X stroke is quite different between them. A 302 is a quicker revving engine, better for HP at higher rev's which isn't ideal for pulling power
 
volaredon said:
I had no reason or desire to leave any of the "stock stuff" in place regarding carb or ignition.
Click to expand...
I left it there only because it is a redundant system. Any problems, I can hook the old stuff up on the fly.
Trailbeast is a user on this site.
 
You can get more torque from the slanty, but normally aspirated, to be significant, it comes at a price of more rpm, more stall and more gear.
All of these run counter to better fuel economy.
Torque + fuel economy, is a tough nut to crack.

Chrysler figured it out pretty good with the lean-burn SYSTEM, and the Dart-Light cars. It's all about light weight, Effective cylinder pressure, and a tiny 2bbl carb with lots of airspeed thru it at low-rpm.. Their only shortcoming was the lack of adequate timing.
 
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DodgeLad said:
I left it there only because it is a redundant system. Any problems, I can hook the old stuff up on the fly.
Trailbeast is a user on this site.
Click to expand...

in my case the underhood wiring was a butchered mess to be "nice" about it so I couldnt wait to gut the wiring in the engine compartment and start fresh with a "new" wiring harness from a junkyard truck. and since the junkyard truck was already a 4 pin ECU harness, I had no desire to add the wiring back in for the Lean Burn.
I might try an HEI swap some day just to compare, I can get all I would need from the local boneyard for practically free.... but for now I aint fixing what aint broke.
 
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