A Teen would be perfect.
Small block mileage
- Thread starter dave ellis
- Start date
-
dave ellis
Well-Known Member
dave ellis
Well-Known Member
I agree
Factory 360 4bl(tired)n my 84 Prospector from Unity Saskatchewan to home in Ontario approx 3300 kms/2000 miles averaged just this side of horrific...around 12-14 mpg...
dave ellis
Well-Known Member
dave ellis
Well-Known Member
Yikes!
MOPAROFFICIAL
Oogliboogli
I've gotten 23 mpg with my 74 dart 318 2 bel. No special tuning. It's mostly about how you accelerate from a stop to get up to speed...and hwy or street.
I drove it routinely to venice beach from fresno and 23 was the mpg.
I've gotten 18 from my 1500 when I had crappy rock hard discount brand truck tires..and the Taylor spacer driving 72 mph on the hwy...but those factory computers actually retard timing under load/acceleration...so you have to stay out of it. They got to 20 from 36-40.
Stick a 500 eddy 4 brl on a stock 360 and that helps quite a bit over any 2 brl.
Slants get only a hair better than a teen, like a few maybe
Your results may vary.
I drove it routinely to venice beach from fresno and 23 was the mpg.
I've gotten 18 from my 1500 when I had crappy rock hard discount brand truck tires..and the Taylor spacer driving 72 mph on the hwy...but those factory computers actually retard timing under load/acceleration...so you have to stay out of it. They got to 20 from 36-40.
Stick a 500 eddy 4 brl on a stock 360 and that helps quite a bit over any 2 brl.
Slants get only a hair better than a teen, like a few maybe
Your results may vary.
Cool truck tho, factory ac, tilt, cruise, am/FM cassette. All worked too! I was basically forced to buy it when in Sask. My 2001 F150 sprung a heater core leak. And I didnt have the know how to deal with removing entire dash(air bags) to repair it. I scoured the ads and found it $1500-2000 I think. 2wd thankfully. If 4wd I bet it wouldnt have hit dbl digits lol
Had a slant/904 2.76 in my 68 dart more door. Usually got 16 or17 mpg jamming at 75 mph. Went to 318/a500 and 3.23 gears usually got 20. Car was 10x more fun to drive too. My 95 ram 1500 4x4 with the 360/518 and 3.5 gear gets 18 empty and under 65mph, 11 flogging it loaded heavy.
just too many variables to say any engine is a “gas hog” and another isn’t. A 500 inch 440 in something light and pointy could get better mpg than a slant in a d500 dump truck
just too many variables to say any engine is a “gas hog” and another isn’t. A 500 inch 440 in something light and pointy could get better mpg than a slant in a d500 dump truck
cudamark
Well-Known Member
I would love to get that much out of my '78 W250 360 4bbl 727 Prospector. I'm lucky to get 9MPG!
When I pulled an enclosed car trailer, I got 6MPG! 
About the only mod is a Holley carb. I'm thinking of going back to a stock TQ and see if that helps any. It's a fairly fresh rebuild with all stock internals and heads for that year, and an RV cam that is supposed to be good for mileage. How much worse would a performance cam have been? Jeeezz....
mygasser
Well-Known Member
a good friend had a 70 coronet with a 318. normal stuff, 4 barrel, headers and dual exhaust. he got 20 ish mpg (uk gallon so bigger than us gallon). we swapped in a similar spec 360 and it dropped to 12-15 mpg, no other changes.
65TerrorCuda
Well-Known Member
I'd a thought the 273 would be a mileage getter vs larger 318's and such but it aint. Every change in heads/intake/etc never made a single mpg difference for me. 13's town/highway.
I see people get 17 with a 273 and am a little jealous!
I see people get 17 with a 273 and am a little jealous!
cudamark
Well-Known Member
Hmm, my 273/904 got 20, and my 273/833 got 22 if I kept my foot out of it. all stock 4bbl. on both, and with standard size tires with 3.23 gears.
65TerrorCuda
Well-Known Member
Wow I'd fall out of my chair if I got that
What is your cars weight, trans, gear ratio & tire size in what year A body?
If you (wisely) ignore the factory tune up specs and give it the hot rod treatment in the distributor and run the crab a hair lean, you can do very well.
The mention of an OD transmission is a nice idea but it can be a bit of a PIA to install and get everything done that needs to be done. Though, once done it does offer a lower first gear to get going easier and quicker along with the OD ratio of .69. Gear ratios work out like this when in overdrive;
Gear ratio multiplied by overdrive ratio for the final drive ratio.
4.10 = 2.829 (2.83)
3.91 = 2.697 (2.70)
3.55 = 2.449 (2.45)
3.23 = 2.228 (2.23)
2.94 = 2.028 (2.03)
2.76 = 1.90
Yes, and even better would be a 5.2`magnum. More compression, thinner rings on oem pistons, better heads, roller cam, and lighter rotating assy.
cudamark
Well-Known Member
Today, I probably can't....with CA's crappy oxygenated "special" blend and the added traffic. This was years ago in my 60 MPH freeway commuters.
True that. I forget about the Magnums but yet I own 2 baby Magnums. (3.9 V6)
I know I will likely take some heat for posting this but chrysler had a decent idea in theory with the lean burn system. I could knock down 24 mpg on the highway and average a bit over 20mpg in my 79 diplomat coupe with the 318. I didn't go anywhere quick though with the 2.2 rear end. That, the lean burn, and the lockup torque converter made a difference and sipped gas.
Last edited:
I don't know anyone that has retrofitted a 500/518 and not loved it. RPM difference is even more than gearing difference when going from a non lockup 904/727 to a lock up overdrive version. Provided someone can do the install and minor fab themselves it is one of the best bangs for the bucks for our old cars and trucks.
I had a HD Sportster that got excellent mileage at slow speeds. Best observation was 60 MPG done at exactly 60 mph with the 1200 engine, 5 spd w/ the typical bolt on mods. Exhaust, ignition, air cleaner and jetting up the carb. At 70/75, mileage was more than a bit less.
But back to cars…..
I had on in a ‘03 Dakota, dead reliable but got less mileage than a 5.2 in the same vehicle. Hence my question to the OP, vehicle weight and such…
The big key was the rear gear at a whoppping 2.2 or was it a 2.45 gear set. I don’t remember a 2.2 gear ratio. When the computer worked the way it should, wasn’t that running on a crazy 17-1 AFR? I wouldn’t suggest that to anyone! LOL!
That’s not the point of argument here.
I said “It could be a PIA to install and have everything done to it to make it work.” As in trans tunnel clears Xing and f need be, trans crossmember fabrication, shortening the drive shaft, angles for the drive shaft, etc….
By saying what you did in that fashion, I feel your taking the context of my words and twisting them into a bay sayer position and that I think it’s not worth the effort and it sucks, period.
Wasn't arguing at all. Just pointed out the benefit of an OD retrofit could be even better than just the gearing.
As far as the install goes, my experience has been it is overstated by some how difficult it is to do. Lots of clearance can be gained cutting the ribs of the side of the trans tailshaft rather than chopping out the torsion bar xmember.
As to the gearset there was both a 2.45 and a 2.2 available in a 7 1/4 rear. The lean burn did go to 16 or 17 to 1 or so but it worked to get the improved cruise fuel mileage.
Oh wow! So there was a 2.20 gear. Yikes! What is that? 95 @ 1100 rpm?!?! LOL!
lemondana
BlackDart
My 67 Dart 273-2 barrel, 904 and a 2.71 8 1/4 rear, 225/70-15 tires got 21 on my last 1000 mile road trip. The 273 has never been apart, never had the valves adjusted with 73,000 miles. Oh! this is with the AC on also. It is gutless, can't even spin the tires-but Oh well.
-
