What MPG are you 340 guys getting?

[340Dust-her]

I'm seeing whether my 340 duster would get some decent mpg since it's coming along together. Nothing crazy, other than a stock 68' 340 with edelbrock performer intake/600 carb, rebuilt 904 transmission. I honestly forgot the gearing in the rearend, but its in the vicinity of 3:4's. Since it is a 3 speed, think it's possible to get at least 18mpg on the highway?

 

[dgc333]

I have a stout 360 (~370 HP) in y 68 Barracuda with an A833OD and 3.55 gears. I get 17-18 mpg around town and 21-22 mpg on the hiway.

 

[340Dust-her]

more info on this A833OD!

 

[crackedback]

Can't say a 340, it's a 360. Got 20 MPG on the highway this weekend.

XE268H, LD340, Holley 750 DP, 2500 convertor, 2.76 gears, Dougs headers.

Probably got a bit more in it with a jet change. It runs a bit fat now.

 

[DERICKS]

68 340 with headers and edelbrock 600 no other changes from stock, 727 trans with 3.21 gears out back gets 18+ cruising 65-70mph on the highway.

 

[72dustyer]

6 sometimes

 

[340Dust-her]

are 904's ecomical or am I better off converting and going to the 727?

 

[71DartGuy]

I would imagine the parasitic loss would be significantly less with the 904 which would be better for mileage.

 

[6dart9]

Look here there is also other posts on this subject for 904 vs 727. I asked the same thng a while back and am sticking with my 340 & 904 set up http://www.forabodiesonly.com/mopar/showthread.php?t=36175

 

[340Dust-her]

sweet, thanks! I'm sure the 205/70R14 tires on all 4 will help too!

 

[crackedback]

904 takes less HP to drive than a 727.

 

[340Dust-her]

I get that. I guess i was assuming the extra gear might help.

 

[MOPARJ]

904 takes less HP to drive than a 727.

Meant to stop by and say howdy on Saturday, Rob, but you seemed to be consistantly busy with customers.

Sunday was just too busy for me. Damn, I missed the car you drove Sunday. I ended up driving away with another Duster on Sunday.

Anyways, my 340/727 combo with 3.23s in my Cuda will pull 17-18 on the highway turning 3K.

 

[Burntorange70]

I got 13.5 on my way to the spring fling this year. Stock 340 3.23's with a 25" tall tire going 70 all the way.

 

[AdamR]

I get that. I guess i was assuming the extra gear might help.

904 and 727s bolth 3 speeds.

 

[Guitar Jones]

5 gallons will make about 7, 1/4 mile passes and of course the trips down the return road and to the staging lanes....so thats about 0.7 MPG.

 

[russduanegreen]

I dont even want to know my MPG

 

[Kevin D.]

I would guess about 6-8 cause I like to hammer it!

 

[340Dust-her]

Doh! I could of sworn, 727's were 4 speed auto's. Thanks for the heads up!

 

[WildCat]

my 340 4 speed with 3.23 in my 67 Dart was about 14 mpg with a 650 edelbrock carb & 10 mpg with 700 dual line double pump holley

for 17 years I owned a 72 Challenger with a 340, 4 speed 3.55 gear and L 60 15 tire and it got about 17 MPG

I had a 77 Aspen T Top, 360 auto and the Challenger at the same time. I drove the Challenger most of the time cause I like the 4 speed and the MPG was almost the same.

 

[jcolman]

Old thread but I thought I'd add my input. Currently running a warmed over 340, mild cam aluminum heads etc. My biggest change was adding a holly sniper. I have 392 rear and a torque flight 727. I'm lucky to get 8 miles per gallon. I think that the sniper is adding more fuel than it should. But my spark plugs look clean. I'm hoping that once I swap over to a Tremec 5 speed I'll see a little improvement on MPG.

 

[rumblefish360]

Old thread but I thought I'd add my input. Currently running a warmed over 340, mild cam aluminum heads etc. My biggest change was adding a holly sniper. I have 392 rear and a torque flight 727. I'm lucky to get 8 miles per gallon. I think that the sniper is adding more fuel than it should. But my spark plugs look clean. I'm hoping that once I swap over to a Tremec 5 speed I'll see a little improvement on MPG.

Anytime you can overdrive it, it’s a good thing for mileage. You may not gain a whole lot but in the seeking mileage game, it’s the little things that get the last little bit that add up. Keep seeking!

 

[harrisonm]

I have a stout 360 (~370 HP) in y 68 Barracuda with an A833OD and 3.55 gears. I get 17-18 mpg around town and 21-22 mpg on the hiway.

Similar except I have a regular 833. Also have 3.55 gears and about 370HP. I'm at about 12 in town and about 16 on the highway.

 

[RustyRatRod]

An 800 or 850 Thermoquad will pounce all over that 600 and get better mileage doin it.

 

[Bewy]

What ^ he said....