Previous Thread
Next Thread
Print Thread
Best combo for mileage? #841819
10/30/10 01:27 AM
10/30/10 01:27 AM
Joined: Jan 2003
Posts: 4,576
Sarcoxie, MO, USA
M
MoPar Jamie Offline OP
master
MoPar Jamie  Offline OP
master
M

Joined: Jan 2003
Posts: 4,576
Sarcoxie, MO, USA
Ok guys, this is mostly carb related but I also have a set of 302 heads at my disposal, the motor in my '86 5th Ave has bottom end issues.

The vehicle is my 1975 D-100 shorty pickup. It has a stock '83 318 2-v with under 100k backed by an A-833OD iron case tranny out of a '76. The rear is original to the frame, an 8 1/4 with 3.55 gears. I am running manual steering and no A/C.

Dry weight without a driver is 3600 lbs, as I took a load of breakage over the scales recently. I'm usually packing tools and parts that add around 100-150 lbs to that. Not to mention my weight that I wont mention.

At first I was getting close to 15 mpg not tuned. Its gone downhill because the re-manned BBD is starting to get cranky. It runs ok but rich and the main gasket is starting to seep.

Anyway I'd like to find the best combo for mileage. I'd love to see 18-20 out of this thing. Do I stick with the 2-v or go with a 4-v? I have a stock iron '84 360 4-v manifold at my disposal.

Now on my heads, is it worth it to throw on a set of "302" heads on an otherwise stock 318? Will I see any gains over my open chambers?

I want this thing to have some get up and go but do decent enough for me to be able to afford to drive it daily. Opinions?


- MoPar Jamie

1972 Fury III 4dr
1986 D-150 LWB Royal SE
Re: Best combo for mileage? [Re: MoPar Jamie] #841820
10/30/10 02:06 AM
10/30/10 02:06 AM
Joined: May 2008
Posts: 5,399
Aurora, Colorado
451Mopar Offline
master
451Mopar  Offline
master

Joined: May 2008
Posts: 5,399
Aurora, Colorado
Some of the throttle body fuel injection setups have dropped in price, and may be an option?
Free flowing exhaust systems usually helps too.

Re: Best combo for mileage? [Re: MoPar Jamie] #841821
10/30/10 02:10 AM
10/30/10 02:10 AM
Joined: Feb 2003
Posts: 10,215
Someplace you aren't
S
SomeCarGuy Offline
I Live Here
SomeCarGuy  Offline
I Live Here
S

Joined: Feb 2003
Posts: 10,215
Someplace you aren't
You have a leaking carb and ask about MPG? Engine not tuned?

Rebuild the damn thing and tune the engine. Then see if you should spend any more money on stuff.

Re: Best combo for mileage? [Re: SomeCarGuy] #841822
10/30/10 09:56 AM
10/30/10 09:56 AM
Joined: Feb 2005
Posts: 5,221
Branson, Mo.
J
joedust451 Offline
super gas
joedust451  Offline
super gas
J

Joined: Feb 2005
Posts: 5,221
Branson, Mo.
Quote:

You have a leaking carb and ask about MPG? Engine not tuned?

Rebuild the damn thing and tune the engine. Then see if you should spend any more money on stuff.




Agreed!!


75 Duster, 451 10.87 @ 123.58 NA 97 Z28 6sp., 12.01 @ 115 on a 100 shot 71 Swinger. 360 magnum. 12.58 @ 105 78 cutlass, 469 BBC. 12.70 @ 108 on street tires. http://www.youtube.com/watch?v=Z2kqNmMfheU
Re: Best combo for mileage? [Re: joedust451] #841823
10/30/10 12:39 PM
10/30/10 12:39 PM
Joined: Mar 2005
Posts: 3,144
Central NC
gch Offline
master
gch  Offline
master

Joined: Mar 2005
Posts: 3,144
Central NC
Once your sort out the obvious issues I would switch to a spreadbore 4bbl.A quadrajet or thermoquad will do wonders for your mileage as lond as you keep your foot out of it.

Re: Best combo for mileage? [Re: MoPar Jamie] #841824
10/30/10 01:07 PM
10/30/10 01:07 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
R
RapidRobert Offline
Circle Track
RapidRobert  Offline
Circle Track
R

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
Quote:

I have a stock iron '84 360 4-v manifold at my disposal.
Now on my heads, is it worth it to throw on a set of "302" heads on an otherwise stock 318? Will I see any gains over my open chambers?
I want this thing to have some get up and go but do decent enough for me to be able to afford to drive it daily. Opinions?


Viewing the eng as an air pump you want to attack the most restricted area 1st which is usually the ex esp as the 318 logs are worthless. I'd use that spreadbore intake (it's actually pretty good) & purchase a Demonsizzler prepped thermoquad & tweak your dist starting w setting the initial/slot length/springs/vac adv (needed) IN ORDER PS yes the 302 heads will help you & been some good info on upping the valve size (iirc from 1.78 to 1.88 plus some bowl hogging (dont remem the angle) & staying w shim gaskets so you dont lose compression which require flat surfaces which you'd have if you did the 302's right but no telling about the block decks for flatmess & w 318 short block rebuilders being cheap I'd actually build one from scratch & get some good pistons & get quench & have a spot on eng from the ground up. W few cubes/alot of weight you need torque which means matched systems & parts/compression/quench so a higher compression will run on pump gas


live every 24 hour block of time like it's your last day on earth
Re: Best combo for mileage? [Re: MoPar Jamie] #841825
10/30/10 01:24 PM
10/30/10 01:24 PM
Joined: Jul 2008
Posts: 30,431
Florida STAYcation
BeEtLeJuIcE ! Offline
The village idiot's idiot
BeEtLeJuIcE !  Offline
The village idiot's idiot

Joined: Jul 2008
Posts: 30,431
Florida STAYcation
CHECK and see if the intake exh-heat-crossover is plugged. VEY commom situation and it will kill MPG big-time.

Re: Best combo for mileage? [Re: BeEtLeJuIcE !] #841826
10/30/10 04:18 PM
10/30/10 04:18 PM
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
R
RapidRobert Offline
Circle Track
RapidRobert  Offline
Circle Track
R

Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
Quote:

CHECK and see if the intake exh-heat-crossover is plugged. VEY commom situation and it will kill MPG big-time.


You know Doc I wonder if that is the prob w my ('83) 318 in a 65 dart (eddy 1406 w streetmaster intake). Mileage is terrible to say the least. I know the 64-66 273 ex manifolds plus a single ex is very restricted


live every 24 hour block of time like it's your last day on earth
Re: Best combo for mileage? [Re: RapidRobert] #841827
10/30/10 04:38 PM
10/30/10 04:38 PM
Joined: Jul 2008
Posts: 30,431
Florida STAYcation
BeEtLeJuIcE ! Offline
The village idiot's idiot
BeEtLeJuIcE !  Offline
The village idiot's idiot

Joined: Jul 2008
Posts: 30,431
Florida STAYcation
RR ..... just saw my spelling on VERY ... it is ruff typing with one handed .... my left hand got nailed by a circular saw.

Those SB intakes are FAMOUS for plugging up. I had a van that was so bad it even plugged-up into the head AND it killed MPG ...I will try posting a pic ...







Powered by UBB.threads™ PHP Forum Software 7.7.1