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Old 11-12-2012, 04:17 PM   #1
GCncsuHD
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Re: How fast does everyone cruise on the highway in their truck?

Well let's see, that should do it:

(disclaimer, speedo was bouncing, It was actually about 90mph)

LOL But seriously, I usually just keep up with traffic, 65-75 depending on traffic flow. I think my 78 with sm465, no overdrive, 4.11 rear, and 35" tires does about 2800 rpm at 70mph.

On a recent trip, about 1.5hrs up unloaded at about 70mph, and 1.5hrs home loaded down with a K5 Blazer on the trailer about 60mph, I averaged just over 10mpg, hand calculated.
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Old 11-12-2012, 09:24 PM   #2
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Re: How fast does everyone cruise on the highway in their truck?

I do the posted speed limit and stay in the far right-hand lane. My MPG never varies, so that's not an issue. I am allergic to red lights in my rearview mirror, especially when they are attached to a CHP vehicle.
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Old 11-12-2012, 09:27 PM   #3
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Re: How fast does everyone cruise on the highway in their truck?

60-65 mph in my '87 Stepside with stock ride height, v6 and 700r4 just feels right.
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Old 11-12-2012, 10:29 PM   #4
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Re: How fast does everyone cruise on the highway in their truck?

If I get a ticket for speeding, I lose my job, so it's the speed limit for me every time.

But, my truck has a big block, no overdrive, and 4.56 gears so I don't really ever have a problem with my speed creeping up too high anyway.
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Old 11-13-2012, 02:54 PM   #5
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Re: How fast does everyone cruise on the highway in their truck?

My '81 scotts has a .030 over 350. Not sure of the gear. it runs 70 like a boss. I actually had the spark advanced a little too far and it liked 70-85 a lot! I need to adjust the vacuum cruise control because it does not hold above 67mph.
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Old 11-13-2012, 08:37 PM   #6
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Re: How fast does everyone cruise on the highway in their truck?

I usually stay close to 55...though I don't do much highway/freeway driving. Something starts vibrating really bad at about 60...haven't figured out what yet.
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Old 11-12-2012, 10:43 PM   #7
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Re: How fast does everyone cruise on the highway in their truck?

I went to Austin and back last weekend and nobody drives under 75 on I35. Most of the trip I was at 85 with a few times past 100, my 454, 4 speed, 4:10 gears and 245/75-16's. Usually I get anywhere from 7-9mpg around town but on the highway I got 10mpg. If I did the same thing and stayed at 75 it probably would have gotten 12. I was not easy on it at all, and I know this is not safe driving habits in a 34yo truck. I'll get a picture next time.
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Old 11-13-2012, 02:21 PM   #8
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Re: How fast does everyone cruise on the highway in their truck?

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I went to Austin and back last weekend and nobody drives under 75 on I35. Most of the trip I was at 85 with a few times past 100, my 454, 4 speed, 4:10 gears and 245/75-16's. Usually I get anywhere from 7-9mpg around town but on the highway I got 10mpg. If I did the same thing and stayed at 75 it probably would have gotten 12. I was not easy on it at all, and I know this is not safe driving habits in a 34yo truck. I'll get a picture next time.
That is entirely possible. I can routinely get 14 mpg highway out of my 79 1 ton with a 502/400 turbo and 3.73 gears with a 29" tire,,,,but I have to cruise at 65 mph and no more, which is right at 2700 rpms. If I bump the speed up to 70ish, I lose about 2 mpg highway.

When I tow my 28 foot trailer loaded (about 10,000 lbs.) I cruise about 60 mph and going accross country I averaged 9-10 mpg highway.

I know what you mean though, most people here drive over the 75 mph speed limit so you have to keep your eyes peeled when cruising along at 65 or get run over. Seems everyone is in a hurry these days. Most times I take back roads if at all possible because of that and prefer a nice relaxed leasurly cruise.
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Old 11-14-2012, 09:34 PM   #9
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Re: How fast does everyone cruise on the highway in their truck?

I am one of the slower guys on the road,my 86 350/465/208 with 4:10 diffs on 35's not really set up for high speed cruising.It probably averages about 10-12 mpg at 100km. My 82. 6.2/A833/208 with 3.73 on 35s does pretty good around 17-19 mpg at 100km. I usually like to sit back and enjoy the ride.I used to drive semi across north america and the company I worked for had a 65mph speed limit and even 15 years later it's still built into my foot!!!! Like I told a fella on the highway once,if your in that much of a hurry,get your a$$ outta bed an hour earlier !!!!!
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Old 11-14-2012, 09:54 PM   #10
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Re: How fast does everyone cruise on the highway in their truck?

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I am one of the slower guys on the road,my 86 350/465/208 with 4:10 diffs on 35's not really set up for high speed cruising.It probably averages about 10-12 mpg at 100km. My 82. 6.2/A833/208 with 3.73 on 35s does pretty good around 17-19 mpg at 100km. I usually like to sit back and enjoy the ride.I used to drive semi across north america and the company I worked for had a 65mph speed limit and even 15 years later it's still built into my foot!!!! Like I told a fella on the highway once,if your in that much of a hurry,get your a$$ outta bed an hour earlier !!!!!
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In my extremely scientific experiment on speed my final result was this: I never got anywhere faster by going faster than the speed limit. In fact I was late most of the time. I totally agree with you.
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Old 11-15-2012, 11:12 AM   #11
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Re: How fast does everyone cruise on the highway in their truck?

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I am one of the slower guys on the road,my 86 350/465/208 with 4:10 diffs on 35's not really set up for high speed cruising.It probably averages about 10-12 mpg at 100km. My 82. 6.2/A833/208 with 3.73 on 35s does pretty good around 17-19 mpg at 100km. I usually like to sit back and enjoy the ride.I used to drive semi across north america and the company I worked for had a 65mph speed limit and even 15 years later it's still built into my foot!!!! Like I told a fella on the highway once,if your in that much of a hurry,get your a$$ outta bed an hour earlier !!!!!
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Agreed, I'm an early riser anyway and like to give myself extra drive time when ever I leave the house. Very simple concept, not sure why other people don't grasp the idea.

I sometimes drive cars with either 4.56 or 4.88 gears and no overdrives, even 55 mph is screaming with a 28" tire. That's even too slow on some of the backroads for people around here

They are either socker moms or just too young to know why I'm driving the speed I am. You would have had to own a classic car to understand. Sad that alot of society today missed out on that.
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Old 11-12-2012, 10:50 PM   #12
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Re: How fast does everyone cruise on the highway in their truck?

i do well at 70 in my c20 with 3.42 and a sm 465 gets me 20-22 depending on grade of fuel. if i go to 75 its 16ish 80 14mpg 85 10mpg
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Old 11-13-2012, 01:46 AM   #13
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Re: How fast does everyone cruise on the highway in their truck?

I drove my 79 350/350 turbo 2/2,5 hours to Olympia Washington a couple months ago at 70/75 most of the way and she ran great the whole way there and back. No idea how many miles the motor has or how many mpg I get. And frankly I dont give a dam lol. When Im in my truck its for fun and I dont care the mpg or the cost to fill it. Thats not why I have it.
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Old 11-13-2012, 09:08 AM   #14
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Re: How fast does everyone cruise on the highway in their truck?

Is that why it feels like the front wheels are coming off the ground at about 85mph??
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Old 11-13-2012, 09:53 AM   #15
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Re: How fast does everyone cruise on the highway in their truck?

79 4X2 has 305-2B@3.4 rear ,quite a change this summer from the 78 $X$
here most speeds top out at 80-100 (50-60)on the highway
over in Quebec tho 90-120+ (55-75) ,keeping up...no prob,
gas mileage drops like a brick lol
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Old 11-13-2012, 08:41 PM   #16
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Re: How fast does everyone cruise on the highway in their truck?

55-60, 357/th350 with 3.40 gears, past 60 I can't look at the fuel gauge.
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Old 11-13-2012, 11:36 PM   #17
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Re: How fast does everyone cruise on the highway in their truck?

60-75 w/3:73 runs great

78 3/4 ton 2wd 4 speed 350
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Old 11-13-2012, 11:38 PM   #18
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Re: How fast does everyone cruise on the highway in their truck?

I cruise at 65 all the time on the highway. With the converter locked in Overdrive, it lopes along a 1900rpm turning 35's with 4.10 gears and averages 14mpg all highway driving...I average just shy of 11mpg average overall. Not bad for a 454TBI crew cab!
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Old 11-14-2012, 12:44 AM   #19
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Re: How fast does everyone cruise on the highway in their truck?

With the price of fuel these days, I keep my speed at 57 mph on my Suburban and get high 20's.
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Old 11-14-2012, 06:55 PM   #20
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Re: How fast does everyone cruise on the highway in their truck?

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With the price of fuel these days, I keep my speed at 57 mph on my Suburban and get high 20's.
I had always wondered if anyone took that into consideration and figured as prices climbed speeds would come down.

Doesn't seem to affect anyone around here though, they all still drive like their a$$ is on fire.
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Old 11-14-2012, 08:10 AM   #21
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Re: How fast does everyone cruise on the highway in their truck?

Yeah areodynamics play a HUGE roll in how much mileage a vehicle gets. Notice how nowadays, even the seams between the door panels and the fenders and the hoods are all getting tighter on the brand new cars? Smaller seam = less drag. And these trucks are like a brick sailing through the wind. They never even considered areodynamics for these things. Would have been pointless anyway. Better that way though cause they look a lot better for it. Notice all the huge headlights and and frontends on the new trucks just sort of blend together in one big blob. Better gas mileage that way.
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Old 11-15-2012, 09:20 PM   #22
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Re: How fast does everyone cruise on the highway in their truck?

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They never even considered areodynamics for these things.
Actually, I remember looking at a brochure from 1972(?) advertising the "new aerodynamic design".
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Old 11-15-2012, 09:46 PM   #23
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Re: How fast does everyone cruise on the highway in their truck?

Yeah, the flat front design idea was used in nascar in the 60's and considered better than what they had previously. Dodge experimented with it on the Charger 500 front ends in 69 with coronet body parts, then sold more than 500 of them to homologate it. It's the same car the nose cones and wings went on which was also homologated and used until Nascar outlawed them, and the rest is history.
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Old 11-14-2012, 06:57 PM   #24
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Re: How fast does everyone cruise on the highway in their truck?

Not me. I do want to do 65/70 though and get somewhere fast. Hell even 70 you get bigrigs passing you.
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Old 11-14-2012, 07:08 PM   #25
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Re: How fast does everyone cruise on the highway in their truck?

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Not me. I do want to do 65/70 though and get somewhere fast. Hell even 70 you get bigrigs passing you.
Yeah, even 70 doesn't scratch the surface around here. Better be in the slow lane

Doesn't bother me though, I go 65ish most of the time regardless. Some of mine are geared too steep to even do that, but that's okay with me. If they want to go faster, they can find another lane and go around.
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