gas mileage - The 1947 - Present Chevrolet & GMC Truck Message Board Network

RT Big Block · 05-25-2013, 10:38 AM

My 75 1 ton with 454 , 4 speed with 3.73 gets around 18 mpg . The worst I have ever gotten with it was 11 mpg but I was loaded 26,000 lbs. Pulling my boats I get around 14 mpg I dont understand why you guys are getting so bad gas mileage. I am getting ready to build a 75 crew cab that I am going to put 427 and 4 speed with U S gear overdrive with 3.73 gear and I am hoping for around 20 mpg with it . I have always done great with gas mileage with big blocks .

lgvl · 05-25-2013, 01:52 PM

I have a similar setup on my 82 454 th400 dually 3+3 but usually get around 11-13 Mpg mixed highway and city. As i've never done the 700r swap i couldn't help you with that question but i can tell you i never speed when the speed limit is over 55mph and i run radial tires versus the chunky truck ones. Also, if you take it easy on the acceleration your gas gauge will thank you.

meatwagon83 · 05-25-2013, 02:12 PM

Quote:

Originally Posted by RT Big Block

My 75 1 ton with 454 , 4 speed with 3.73 gets around 18 mpg . The worst I have ever gotten with it was 11 mpg but I was loaded 26,000 lbs. Pulling my boats I get around 14 mpg I dont understand why you guys are getting so bad gas mileage. I am getting ready to build a 75 crew cab that I am going to put 427 and 4 speed with U S gear overdrive with 3.73 gear and I am hoping for around 20 mpg with it . I have always done great with gas mileage with big blocks .

im callin shenanigans on this one!

RT Big Block · 05-25-2013, 05:11 PM

Quote:

Originally Posted by meatwagon83

im callin shenanigans on this one!

I know you dont believe me but its true ! I worked for GM for 15 years . And I do know how to get mileage out of a big bock and its real easy to do . I guess it does help I have a friend that was a engineer at GM too.

meatwagon83 · 05-25-2013, 06:41 PM

Quote:

Originally Posted by RT Big Block

I know you dont believe me but its true ! I worked for GM for 15 years . And I do know how to get mileage out of a big bock and its real easy to do . I guess it does help I have a friend that was a engineer at GM too.

Well by all means share with the rest of the class! I know I for one would love to get another 10mpg out of my truck!
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LynnJr · 05-25-2013, 06:55 PM

I'm getting 10-12 with a 1/2 ton short fleetside 3.73 rear and hard tonneau cover slammed on the ground with th400.

05-25-2013, 10:38 AM	#1
RT Big Block Registered User Join Date: Mar 2013 Location: West Plains MO. Posts: 6	Re: gas mileage My 75 1 ton with 454 , 4 speed with 3.73 gets around 18 mpg . The worst I have ever gotten with it was 11 mpg but I was loaded 26,000 lbs. Pulling my boats I get around 14 mpg I dont understand why you guys are getting so bad gas mileage. I am getting ready to build a 75 crew cab that I am going to put 427 and 4 speed with U S gear overdrive with 3.73 gear and I am hoping for around 20 mpg with it . I have always done great with gas mileage with big blocks .

05-25-2013, 01:52 PM	#2
lgvl Registered User Join Date: Mar 2013 Location: Rochelle, Il Posts: 63	Re: gas mileage I have a similar setup on my 82 454 th400 dually 3+3 but usually get around 11-13 Mpg mixed highway and city. As i've never done the 700r swap i couldn't help you with that question but i can tell you i never speed when the speed limit is over 55mph and i run radial tires versus the chunky truck ones. Also, if you take it easy on the acceleration your gas gauge will thank you. __________________ '82 C30 3+3 Dually 454

05-25-2013, 06:55 PM	#6
LynnJr Registered User Join Date: Nov 2012 Location: santa rosa,california Posts: 650	Re: gas mileage I'm getting 10-12 with a 1/2 ton short fleetside 3.73 rear and hard tonneau cover slammed on the ground with th400.



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