How to get a 5.0 to tow better

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kauila

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The type of tires on the truck can make a difference in gas mileage. I use BF Goodrich Commercial LT 245/75R16 M&S tires pumped up to 80 psi on my truck. Some people use softer tires on their trucks and I would expect that it would give them more rolling resistance.
 

L31MaxExpress

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There's no way you only get 14 mpg highway in a 5.0 lol, I would guess 18 or so. Heck, even my K3500 CCLB 5.7 obtained 16.8 mpg once, given it was onflat roads at 5600 ft elevation burning Supreme fuel, but still.

My 99 Tahoe would get 21-22 running about 70-75 mph on the highway. Lunati 268 flat tappet cammed (Old Style Rhoads Lifters) 305 Vortec, 4L60E and 3.42 gears. Truck was on P305/50R20s. Long tube headers, dual 2.5" exhaust to the muffler with high flow cats, tuned 0411 PCM (Lean Cruise Enabled) and 2010 Tahoe E-fans.

I had the ~300K mile 305 down to the bare block before it went into the Tahoe. New bearings, new rings, new gaskets, a new cam I had laying around and a new timing set. Polished the crank, cleaned the stock pistons, honed the block and ran. Ended up with a bad mellings lifter that kept collapsing and swapped the whole set to the Rhoads lifters as that cam was fairly aggressive in an otherwise stock 305. Added some low end torque and vacuum but kept the mid-top end power. S10 converter went from brake stalling 2,200-2,300 up to 2,400-2,500 after the lifter change.

On long hills with a 4,500 lbs trailer it was foot on the floor in 2nd gear at 70 mph going up the hill. Turning about 4,500 rpm.
 
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JeezLouiseGMC

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How many of you who are calculating mileage have calibrated your speedometer? The other question is how accurately does the odometer track with the speedometer?
it didn't even occur to me that the uncalibrated speedometer would throw off the odometer.. i know mines 4-5mph fast so that's interesting..
 

Supercharged111

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it didn't even occur to me that the uncalibrated speedometer would throw off the odometer.. i know mines 4-5mph fast so that's interesting..

Like I said, I never compared odometer to real world myself. My hope is that a corrected speedo reels it all back in, but who knows?
 

L31MaxExpress

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Like I said, I never compared odometer to real world myself. My hope is that a corrected speedo reels it all back in, but who knows?

I set my speedos to be accurate at 70 mph. Odometer is accurate mile post to mile post on the interstate.
 

JeezLouiseGMC

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Like I said, I never compared odometer to real world myself. My hope is that a corrected speedo reels it all back in, but who knows?
Well with my speedometer reading fast that means it should still give me a higher mpg than if it was correct right? because its reading more miles than I actually put on it? meaning my 14.7 is an optimistic measurement
 

Supercharged111

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Well with my speedometer reading fast that means it should still give me a higher mpg than if it was correct right? because its reading more miles than I actually put on it? meaning my 14.7 is an optimistic measurement

Bingo, I too felt that kick in the nuts years ago.
 
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