Big Block A body Mileage?

-
J

jeeper

Well-Known Member
Joined
Jul 13, 2005
Messages
1,076
Reaction score
32
Location
Klamath County, Oregon
Hello all,

I am gathering parts for my 360 A body right now and it is going well. That being said, I have come across more big block stuff lately.

I have a 74 Duster that would accomodate the 440 real well.

I am aware that we don't build these cars for economy, but I do drive a minimum of 35 miles everytime I start the car. No less due to my location.

Assuming a mild 440, mid 3.00's gears and the Shumacher headers, any one have experience with mild 440's and mileage?

I have a sneaking suspicion that it will be better than my 4.10 geared .484 cammed 360........

Thanks for your help as always, ROB
 
My son's 440 is getting a bit tired, but we have gotten around 15mpg with the four speed and 3.23 gears. Right now it's about 11-12 on the highway.
 
I wonder what built small blocks get?

I just checked mine and I got mid 14's for MPG. I think I would do better on a long trip without a long warm up etc.

It is a dead stock 318 2v in a 73.

I think I could live with 15 MPG out of a big block.
 
For what it's worth. Back in the 80s I used to get 18mpg with my 273 four barrel, four speed 66 Barracuda and 17mpg with my 68 GTS convertible 340/727. Both cars also had 3.23 gears. The Barracuda had a sure grip.

Fuel changed between 89 and 92 while I had the engine out of the GTS. I never got better than about 14mpg after putting the car back together. The only differences in engines were compression and bore. The old engine was a standard bore 73 short block with 8.5 pistons. The newer engine is a .030 over 10.5 motor. Heads, cam, etc were all the same. The car hasn't been on a long trip in a long time, so I don't know what it would do with today's fuel.
 
My Slant Six 'Cuda gets about 11 mpg on the highway... 3.91 gears with a 26" tire... that's going about 70ish spinning about 3500 rpm... hope that helps... complete opposite spectrum of a big block, but gas mileage is gas mileage in my book! :thumblef:
 
Mileage? I think I measure gallonage with this BB beast. I get about 7-8 mpg in the city and about 10 on the highway. The rear has 4.30s and I run a 27" street tire.

Greg
 
LOL, big block are know to have crummy mileage. I remember a girl posting about hers and how to get more. At the time, she was getting a posted 17-18 on the Hwy. I thought it was good.
I get about 13 in my '79 Magnum on the Hwy. 400/727/3.21 and 26 inch tires.

Sqeaking out mileage with a big block is counter productive to seeking power. I think the easy things need to be done first before you start and try to re-engineer.
Once you start changing cams and etc... your done and it's over.
 
I know enough to not ask about mileage, but I did anyways.

You should see what happens when you ask on a truck site.....It gets almost ugly.

The deal is that I am getting a 440 on Sunday and I am contemplating using it for my other Duster. Just thinking and considering at this point. I still have to get the one I drive done so this is a long term deal.

When I build a 4x4, I rarely go under a 38" tire. I like how smooth they will tackle obsticles. The same thinking could apply here as far as a bigger tool to do the same work.

My thinking was a larger engine, turning less RPM, in a milder state of tune could get me similar acceleration with the same or better MPG.

I like to drive my cars and I have no choice right now. I used to live in town. Mileage did not matter then.

Thanks for the replies, ROB
 
Oh, one more thing. Years ago I had a friend with an original 68 383/727 GTS. He lived in Sunnyvale, CA and was going to school in Northern Idaho. He threw a set of 2.76s in the 8-3/4 and fine tuned it and was getting about 22mpg on the highway. Top end was impressive, too.
 
I checked my first tank of my 68 Valiant /6 auto, 13" tires. not sure on the gears 2.?? I got 22 mpg, but thats Canadian.
 
I think the other reason for my poor mileage is my really heavy right foot! I know I can't be the only one with this horrible condition.

Greg
 
While I have no idea what mileage is now since it isn't together yet, I had the same engine in my 68 Roadrunner with the OD 4 speed and 3.91 gears and drove it from Louisville, KY to Chicago and got 15mpg at a steady 60 mph. I checked the mileage with a working odometer in my wifes car that I was following. I bet with the heavy right foot that I used in normal driving that car was around 6mpg at best, lol.
 
Jim Lusk said:
Oh, one more thing. Years ago I had a friend with an original 68 383/727 GTS. He lived in Sunnyvale, CA and was going to school in Northern Idaho. He threw a set of 2.76s in the 8-3/4 and fine tuned it and was getting about 22mpg on the highway. Top end was impressive, too.
Click to expand...
I have heard of this type of mileage before from big blocks. You need a mello engine, basicly a stock unit with those gears and a reasonable tire size to do it.
 
You must log in or register to reply here.
-

Back
Top