Chevy 5.3 Vortec Fuel Economy? (1 Viewer)

[srgould41]

I have a carbed 305 in front of a 700R4. I am getting about 11 mpg highway on 33's and stock gearing.

I may consider a 5.3 later on.

What kind of highway fuel economy are you guys with 5.3's getting?

 

[bomb69tech]

Not sure about highway driving but I know a full day on the trail and I burn about 1/8 of a tank maybe a hair more.

 

[srgould41]

Do you own the silver 40 that was in 4WD Toyota Owner mag?

Not sure about highway driving but I know a full day on the trail and I burn about 1/8 of a tank maybe a hair more.

 

[srgould41]

I had always planned a 5.3 in the future when my motor wore out or I got sick of the lack of power. I went with the 305 because I only paid $250 for it. I keep watching fuel prices go up. A tank of gas is now $70. So I was just thinking about the return on investment on a 5.3 swap as it should net better economy as well as more power. How much better is the question.

That said, I do NOT have the money right now. And my wife would freak like never before if I came home with another engine

It's worth considering though

Damn Steve. I can see why your wife took away the checkbook.

Have you got 100 miles on that engine you just put in? You really need to drive what you have for a couple of years before changing it again.

 

[green40]

This guys driving a 60,
https://forum.ih8mud.com/60-series-wagons/223607-vortec-5-3l-fuel-economy.html

 

[JackA]

My 40 with a 2004 5.3 got about 14 mpg. That's mostly around town with a th350 trans, 4.11's, 35 MT's and a heavy right foot.

A friend that has a 5.3 Tahoe says his wife gets 20 mpg driving it.

 

[Fast Eddy]

My 40 with a 2004 5.3 got about 14 mpg. That's mostly around town with a th350 trans, 4.11's, 35 MT's and a heavy right foot.

A friend that has a 5.3 Tahoe says his wife gets 20 mpg driving it.

My 40 with a 2f gets 13mpg average for a light wheeling weekend.

My wife's lowered 2wd Suburban with a 5.3 can get 22mpg on a long freeway trip.

Point being that the shape of the truck makes more difference than the engine.

 

[yzftaco]

To me the benefits of the improved gas mileage ON THE TRAIL would be huge..

I have a carbed 350 and my rig sucks the gas on a wheeling trip, I have to add fuel to get thru.

my buddy who has an injected 350 barely uses 1/8-1/4 tank for the same trip.

 

[srgould41]

I was kind of wondering if it was realistic to see about 15 mpg highway. The difference between 11 and 15 mpg means the engine could (if under $1k for a good used engine) be paid off after 55 tanks of gas.

 

[elbigsam]

my brother posts here as effjay76, hes got a 350 with a edelbrock performer 4 barrel, toyota 4speed, 35 inch muds. hes at 14 on the highway......you got robbed bro.

 

[bomb69tech]

Do you own the silver 40 that was in 4WD Toyota Owner mag?

Yes that is mine. Got my copy yesterday.

 

[JackA]

My 40 with a 2f gets 13mpg average for a light wheeling weekend.

My wife's lowered 2wd Suburban with a 5.3 can get 22mpg on a long freeway trip.

Point being that the shape of the truck makes more difference than the engine.

That was my point. Like the Tahoe has overdrive and street tires too. Basically saying a 5.3 can do better than 14. The 40 is not a vehicle built for mileage though. If you are concerned with gas mileage, a V8 Cruiser may not be a good choice.

 

[srgould41]

My V8 gets the same or better than the 1F did. So I am no worse off. I am just wondering if I can improve it and if it's cost effective. My engine only has about 150 miles so I will get it improved upon. I know I am running rich, plus my 700R4 didn't have a locking converter which will make a difference when I get the new tranny in.

That was my point. Like the Tahoe has overdrive and street tires too. Basically saying a 5.3 can do better than 14. The 40 is not a vehicle built for mileage though. If you are concerned with gas mileage, a V8 Cruiser may not be a good choice.

 

[bikersmurf]

I'd think you've got some room for improvement on your 305. With my 350, I can get about 15 mpg on the highway. Quadrajet, RV cam, dual exhaust, 33s, and 4.11s.

 

[Sepuku]

Go Fuel injection and keep it simple with a gen 2

 

[centerlineseal]

I've got a EFI 350 out of a 1999 Suburban in front of a 5 speed NV4500, stock 4:11s in the '75 FJ40 on 33" Toyota M55s. I get 15 mpg on almost any highway trip here in Idaho, mountains and all, driving 55 to 65 mph.

BTW, back in 1976, I got 18 mpg with my 1F, 3 speed stock '72 FJ40 going thru central Nevada on highway 50. Less than 60 mph or so, back when gas even smelled sweet!

 

[effjay76]

my brother posts here as effjay76, hes got a 350 with a edelbrock performer 4 barrel, toyota 4speed, 35 inch muds. hes at 14 on the highway......you got robbed bro.

yeah i get 14 mpg at around 60 mph with the aforementioned stuff and 4:11's. Its a 1984 crate motor "hecho in mexico"

 

[effjay76]

I also have the edelbrock air gap intake manifold, headers, and a mandrel bent exhaust system.

 

[srgould41]

I guess I'll be spending some time tuning when I get my rig back together. Thanks for all the info!