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Old 02-07-2010, 01:36 AM   #1
munger
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88-90 454 gas mileage

ss or a work truck
they would have a th400 im thinking about getting a 89 1 ton but i wanna know some mpgs
thanks
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Old 02-07-2010, 01:48 AM   #2
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Re: 88-90 454 gas mileage

i was told 10 tops.anyone else?
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Old 02-07-2010, 03:31 AM   #3
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Re: 88-90 454 gas mileage

7, all day everyday, wether Im driving 3 miles or 300 miles, I avg 7 in mine, 1988 C3500 Extended Cab Dually with 74,400 on orig. Motor Trans and Rear End...

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Old 02-07-2010, 03:43 AM   #4
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Re: 88-90 454 gas mileage

What gears do you have
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Old 02-07-2010, 12:28 PM   #5
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Re: 88-90 454 gas mileage

Gears don't really matter. I owned a crew cab dually 4x4 and 2wd. Most I ever saw was about 8 on rainy days. 7 mpg. No matter what. Cold, hot, empty, pulling 15,000 lbs, a/c on, etc.

These things will kill you on gas cost if you aren't working the engine. And it takes a LOT to work a 454. They are great tow rig engines. I live 6 miles from town. 2 gallons of gas for a town trip. When gas was $4.00 a gallon and I was making 10 dollars an hour, well yeah...hours pay for a trip to town sucked.
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Old 02-07-2010, 01:58 PM   #6
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Re: 88-90 454 gas mileage

We used a '97 crewcab, 454, auto, 410gears, 1ton for 30,000mi. to tow a 8500# travel trailer. 7-8 towing, 10 tops, no trailer. Still like the old gas guzzling brutes.

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Old 02-07-2010, 03:02 PM   #7
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Re: 88-90 454 gas mileage

I agree gears don't seem to matter on mileage. In my '88 extended cab single wheel one ton, I swapped the 4:10s for 3.21s. Barely made any difference at all, but rolls down the highway much nicer & quieter now.

Absolute best I ever got was 12 driving "MPG style" with a topper on it. 10 most of the time. 6-7 pulling a bumper hitch car trailer with a 5,000 lb. pickup on it.

I rebuilt it a few years ago adding a small RV grind Comp hyd. roller cam, Edelbrock intake, better breathing '96 exhaust manifolds, took the melted down cats out... it didn't improve mileage one bit.

My '72 K20 with 4.10s, Cad 500 and a Qjet does just as good, if not a little better towing.
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Old 02-07-2010, 04:24 PM   #8
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Re: 88-90 454 gas mileage

wow i didnt think it would be that bad maybe ill be better off getting a 81 3/4 ton 350/4 speed
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Old 02-09-2010, 01:25 AM   #9
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Re: 88-90 454 gas mileage

Quote:
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wow i didnt think it would be that bad maybe ill be better off getting a 81 3/4 ton 350/4 speed
14 mpg with mine in a '77 4x4 stick shift and rising.......stock air cleaner and exhaust manifolds help a lot, even though the engine itself is bored out with Edelbrock goodies sitting in it.
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Old 02-09-2010, 03:39 PM   #10
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Re: 88-90 454 gas mileage

in order to get decent milage out of a 454 you need to bump the compression up to 10:1 and get a good set of headers and you'll see 13-15mpg all day
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Old 02-07-2010, 05:30 PM   #11
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Re: 88-90 454 gas mileage

i get about 8mpg in my 90 454ss truck, thats why its getting a 4L80e.
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Old 02-09-2010, 12:26 AM   #12
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Re: 88-90 454 gas mileage

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a 89 1 ton
I used to drive one, a K3500 with 4.11 gears. Driving to and from work it did 7 or 8 mpg. On the highway it would do about the same, though driven carefully it might get 9.

My best tank was 10 if I can round up generously. My worst was about 3 pulling a trailer and fighting a head wind that was strong enough I was told a couple of semi trailers were knocked over by it.

With a 35 gallon tank it often cost $100 plus to fill it.
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Old 02-16-2010, 05:59 PM   #13
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Re: 88-90 454 gas mileage

Of the 2 454SS trucks I have owned, the one with T400 would get 10-12 mpg and the other with a 700R4 replacement trans would get 16 on interstate. Overdrive definitely helps, both had 3.73 gears.
The one I have now with the 572, well.... who knows what it will get, but who cares, all I want to do is finish it so I can enjoy it.

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Old 02-16-2010, 11:51 PM   #14
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Re: 88-90 454 gas mileage

87 crew cab shortbed tbi 454\400 308 gears 6 to 7 mpg full or empty. thats why its getting a 5.3 4l60e. Jay
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Old 02-17-2010, 01:50 PM   #15
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Re: 88-90 454 gas mileage

Quote:
Originally Posted by BayouSS View Post
Of the 2 454SS trucks I have owned, the one with T400 would get 10-12 mpg and the other with a 700R4 replacement trans would get 16 on interstate. Overdrive definitely helps, both had 3.73 gears.
The one I have now with the 572, well.... who knows what it will get, but who cares, all I want to do is finish it so I can enjoy it.

Bill
are you over on North american truck club??? www.454ss.com

Name looks familiar

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Old 06-10-2010, 07:08 PM   #16
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Re: 88-90 454 gas mileage

Just measured the 1992 I just got. With 75% highway driving at 5 over the speed limits and accelerating slowly I was getting 13.5 MPG with stock filter and 14.5 with K&N. This is with a topper on it and unloaded otherwise. Bought the truck to haul 10,000 pound trailer so can't wait to see what it gets then!
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Old 06-13-2010, 10:29 AM   #17
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Re: 88-90 454 gas mileage

I get anywhere from 8-10 mpg out of my 1990SS and the drivetrain is stock, well minus the smog stuff. My 2003 1500HD 4x4 CCSB gets 11-12 and that's a 6.0 with a 4 speed auto. I believe both of my trucks have a 3.73 gears.
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Old 06-14-2010, 11:43 AM   #18
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Re: 88-90 454 gas mileage

Wow a lot of SS owners coming out of the darkness for this thread. I like to see that.

We used to have a 1 ton dually here at the store, and it was like the others have said. It got about 8mpg all day long. Loaded, empty, etc...
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Old 06-14-2010, 01:15 PM   #19
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Re: 88-90 454 gas mileage

Quote:
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It got about 8mpg all day long. Loaded, empty, etc...
...engine off, coasting, you should still get about 8 mpg....

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