Smallblock efficiency or How to have your cake and eat it too

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Its not all that hard, if I could get constant 14.5 mpg out of an old brick 1978 4X4 power wagon, anything with aerodynamics is going to do better.
 
I run a 340 with everything RAMM has talked about so far except my cam is [email protected] (to small and upgrading soon) and an A999 low gear set. I burn 7 gallons of 93 driving 100 round trip and run 5 1/4 mile passes. I've never checked mileage just cruising.
Following.
 
Yes this thread is going sideways. J Rob, what is your idea of good mileage with the 340 you talk about? I get 20 with my 318 2 barrel Swinger and 19 with my 4 barrel 273. The teen has about 50,000 miles on it and the 273 is fairly fresh with about 10,000 so neither are worn out. You always hear stories of old C bodies with 383's getting close to 20. 2 barrel I'm sure and with a 2.... rear gear as well. Just curious what your expectations are.
 
toolmanmike said:
Yes this thread is going sideways. J Rob, what is your idea of good mileage with the 340 you talk about? I get 20 with my 318 2 barrel Swinger and 19 with my 4 barrel 273. The teen has about 50,000 miles on it and the 273 is fairly fresh with about 10,000 so neither are worn out. You always hear stories of old C bodies with 383's getting close to 20. 2 barrel I'm sure and with a 2.... rear gear as well. Just curious what your expectations are.
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19-20 mpg and 450-500+HP. Just a little more than an anemic 318/383 2bbl. Hence the title. J.Rob
 
I used to drive my 68 barracuda with a 318 4 bbl and got 17.75 mpg with a 2.76 axle....

My dad had a bone stock 76 Charger with a 360 that got 20 MPG and had a 25 gallon tank = 500 mile range...

18 - 20 MPG is not out of the question...
 
I have a 410 stroker in my aussie charger. it weighs around 3100lbs . On a recent trip to our annual chryslers on the murray meeting 550 kls (350miles) I got 21 mpg going down and 22mpg comming back sitting on a comfortable 120 kph (about 75 mph) My car has a 410 with 236 @ 50 thou roller hyd cam with edelbrock heads 800 avs carb five speed manual box and 3.91 diff ratio. The best thing I ever bought for the car was the air fuel ratio guage that has enabiled me to tune this car so good. It has run a best of 11.4 down the qtr but yes I do lighten it by taking bumpers,sway bars and passenger seat out to run these times. With the five speed and 28 inch tyres it cruises at 110kph(70mph) @ 2400rpm. Just in a niece torque curve and very pleasant drive! I know our imperial gallon is slightly larger than your US gallon but I think that is really impressive considering my 351 clevelands in the early eighties could do no better than 15mpg even with there 2.76 diff ratios in standard form. Hell even back in the seventies my 340 charger with sic pack and 3.91 diff would get 21mpg it is just hard to not use that right pedal too much but with all the HWY Patrol Cars on our road networks and the large fines and pionts systems it is a big deterrent to keep the speeds down compared to the early seventies.
 
James Clews said:
I have a 410 stroker in my aussie charger. it weighs around 3100lbs . On a recent trip to our annual chryslers on the murray meeting 550 kls (350miles) I got 21 mpg going down and 22mpg comming back sitting on a comfortable 120 kph (about 75 mph) My car has a 410 with 236 @ 50 thou roller hyd cam with edelbrock heads 800 avs carb five speed manual box and 3.91 diff ratio. The best thing I ever bought for the car was the air fuel ratio guage that has enabiled me to tune this car so good. It has run a best of 11.4 down the qtr but yes I do lighten it by taking bumpers,sway bars and passenger seat out to run these times. With the five speed and 28 inch tyres it cruises at 110kph(70mph) @ 2400rpm. Just in a niece torque curve and very pleasant drive! I know our imperial gallon is slightly larger than your US gallon but I think that is really impressive considering my 351 clevelands in the early eighties could do no better than 15mpg even with there 2.76 diff ratios in standard form. Hell even back in the seventies my 340 charger with sic pack and 3.91 diff would get 21mpg it is just hard to not use that right pedal too much but with all the HWY Patrol Cars on our road networks and the large fines and pionts systems it is a big deterrent to keep the speeds down compared to the early seventies.
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Impressive
 
72Dart6pack said:
You have the impression that we are all stupid. Not the case.
:wtf:
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Dude? WTF?

RAMM said:
Not sure where youre coming from but I talk to people who want their engine built almost everyday and they have no clue about this stuff. Sorry if I'm stating the obvious to you, feel free to stop following along. J.Rob
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Here here!
RAMM said:
I agree with everything you said but that is getting off topic. This thread is more about what we can do with our old antiquated V8 architecture wihin reason. J.Rob
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Now this is what I'm talking about.
 
One tidbit... if you run higher compression with good squish the engine will take leaner mixtures better thus saving fuel. I noticed a big difference in how my current 9:1 360 with open-chamber Edelbrocks responds to different AFRs compared to my old 360 with Magnum heads, 10.5:1 SCR and KB flat-tops... Just going from ~13:1 AFR at WOT down to 12.2:1 feels like I picked up 50 HP on my new mill. My old engine felt the same with 13:1 or 12:1 AFR, using the same carb, headers and exhaust system to boot. Applies to part-throttle cruise as well, you can lean it out more before it starts misfiring/surging and burning things up.
 
My previous 367 iteration went, up to 32mpg, and went over 106 in the quarter/ around 85 in the Eighth.
Then I went to one size bigger cam, and now the mileage is lousy. The only other changes I made were; a tiny change in cylinder pressure and I swapped the weeney600 for a 750DP? What could be wrong? lol.
Oh wait, I changed from an 8-speed with double overdrive cruising 65=1590, to a 5-speed with single overdrive cruising 65=2240........... and I ditched 200 pounds for the day. Oh well; car now goes 93 in the Eighth! Due to the approximate 8mph grin-factor, I no longer care about mpgs.
I tried to talk my wife into a Smartcar, but she says they are a deathtrap, and a Flintstones car; and she won't be seen dead in one..And she should know,lol; in 42 years of wedded bliss, she has crashed or written off almost every car we have ever owned. Ok, I killed two but they weren't my fault! Well two if you don't count the other two...
For those who want to know;
the 8 speed was the combo of A833od box plus GVOD, splitting gears. and
the 5 speed is the combo of Commando-A833 plus GVOD.

Point is I get what you are saying; and it's not always, nor totally, about rpm.Sock it to me.
 
AJ/FormS said:
My previous 367 iteration went, up to 32mpg, and went over 106 in the quarter/ around 85 in the Eighth.
Then I went to one size bigger cam, and now the mileage is lousy. The only other changes I made were; a tiny change in cylinder pressure and I swapped the weeney600 for a 750DP? What could be wrong? lol.
Oh wait, I changed from an 8-speed with double overdrive cruising 65=1590, to a 5-speed with single overdrive cruising 65=2240........... and I ditched 200 pounds for the day. Oh well; car now goes 93 in the Eighth! Due to the approximate 8mph grin-factor, I no longer care about mpgs.
I tried to talk my wife into a Smartcar, but she says they are a deathtrap, and a Flintstones car; and she won't be seen dead in one..And she should know,lol; in 42 years of wedded bliss, she has crashed or written off almost every car we have ever owned. Ok, I killed two but they weren't my fault! Well two if you don't count the other two...
For those who want to know;
the 8 speed was the combo of A833od box plus GVOD, splitting gears. and
the 5 speed is the combo of Commando-A833 plus GVOD.

Point is I get what you are saying; and it's not always, nor totally, about rpm.Sock it to me.
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I didn`t read all these posts, and don't give a flip about the topic , either way.
The opening statement that all true muscle cars have 3 pedals dropped my interest. The op doesn`t think the 68 s/s hemi barracudas and darts aren`t muscle cars / 454 chevelles/ 65/66/67 hemi belvederes ????????
Don't for get the bone showroom stack 440 auto charger that even Steve Mcqeen couldn`t believe would smoke his special built mustang on the hi way----
 
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My 340 gets about 80 miles out of a 10 gallon tank...and uses a 1/2 litre of oil at the same time, I would aim for something better than that with your build and I’m sure you’ll be successful...

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stixx said:
Whew, your oil consumption is pretty bad. That's roughly 4 Liters on a 1000K... :eek:
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Yeah it’s getting refreshed in the next few weeks now that the weather has finally warmed up...hone,gaskets and rings,might switch out the high volume oil pump for a stock one.

But back on topic this thread is interesting as it is kind of my goal with the magnum I’m currently building for one of my other cars...I want it to run 13’s, run on 87 octane with a 727 and 2.76 gears...
 
rumblefish360 said:
Cough cough cough

Bullshit

:bs_flag::bs_flag::bs_flag::bs_flag::bs_flag:
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It was actually 40 mpg per Canadian gallon,lol.
And there were times on the freeway that we were actually cruising at higher than 65=1590; just to not be a danger to the traffic around us.

As can be combined from what others here have said, the co-ordination of; cylinder pressure,ignition timing, a hi running temperature, the right cam timing events, and rpm, combine to allow amazingly lean AFRs. And I have a pet theory about what the aluminum heads are doing to make such results possible.
The clutch is just the icing on the cake.
I am very much looking forward to seeing RAMMs results.
 
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A lot of stock 340's got 20 mpg back in '68 and '69.They really are the best all around engine in an A body!
I know a lot of guys with big blocks, big and small strokers or nasty small blocks that won't go to cruz night get togethers if they are more than 6 or 7 miles away just because of poor mpg.
 
famous bob said:
I didn`t read all these posts, and don't give a flip about the topic , either way.
The opening statement that all true muscle cars have 3 pedals dropped my interest. The op doesn`t think the 68 s/s hemi barracudas and darts aren`t muscle cars / 454 chevelles/ 65/66/67 hemi belvederes ????????
Don't for get the bone showroom stack 440 auto charger that even Steve Mcqeen couldn`t believe would smoke his special built mustang on the hi way----
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No need to get offended about my 3 pedals comment, it's just how myself and a few others feel. Also in case you don't understand the intent of this thread--a manual driven properly is MORE efficient at power transmission than an old slush box.

Totally agree with you on the Bullit as that is what I get out of that whole scene too---The Charger just effortlessly loafing along while Steve is frantically shifting his 9 or 10 speed transmission in order to keep up. J.Rob
 
krazykuda said:
I used to drive my 68 barracuda with a 318 4 bbl and got 17.75 mpg with a 2.76 axle....

My dad had a bone stock 76 Charger with a 360 that got 20 MPG and had a 25 gallon tank = 500 mile range...

18 - 20 MPG is not out of the question...
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A lot of you keep missing the 500HP AND 19-20 mpg part. I don't care about stock 318's/340's,360's,383's etc.... that did or could have gotten 20 mpg-ev.en still they would be the exception rather than the rule

Your Dad's bone stock Charger with a 360 had no where near 500 hp.

Oddly enough my father had that exact car when I was a baby, was yours blue with a white vinyl top and interior? lol. J.Rob
 
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