Mileage question..doh

[dezertxj88]

Mileage wise on a stock 350, what rpm would you want to be at for the best mileage? The GM 350 peaks around 2200-2500rpm..so cruising at 60-65mph I would want around 2200rpm correct?
K10 4x4, sm465, np208...4.10s and 38x13's gets me at 2300 rpm give or take. Should I gear deeper than 4.10's? Probably drop down to 37x12.5 or 36x12.5's honestly. This is a daily driver.
Now that the burb is mine, I'm thinking of selling all my old jeep parts, around 1200-1500 & rebuilding the gm 350, or swapping in a 5.3L vortec & keeping the carb...going to research this up as well!


And if you see my previous thread, I traded my Xj for the BBB, big blue burb + 1200 cash tonight! Soon to take on a desert tan paint job with a white/ceramic painted/coated roof, military take offs & whatever else to gear it towards a military theme!

 

[ChrisPerry]

I've always been told 2700-3000 rpm @ 65 mph is good for an all around driver and 2400-2700 rpm for fuel econ. Here's a common chart......

http://www.4wheelonline.com/superlift_tiresize.htm

 

[dezertxj88]

Honestly the chart is pretty close...I get 2356 rpm for 4.10's & 38's.

Mileage wise will I ever see 15mpg highway on 36's? 4speed, 350 & 4.10's

 

[Hogback Fabrication]

Honestly the chart is pretty close...I get 2356 rpm for 4.10's & 38's.

Mileage wise will I ever see 15mpg highway on 36's? 4speed, 350 & 4.10's

When I daily drove my Blazer with a 465, 4.56's and 37's I would average 10-12 just driving it, 12-13 highway only with a best of 14.5. That's all with the 383, it was a little worse with the stock 350.

I wouldn't count on 15 without an overdrive or a diesel, the 5.3L has a way better chance for better mileage.

 

[big dan]

Mileage wise will I ever see 15mpg highway on 36's? 4speed, 350 & 4.10's

Good luck

My truck, 3.73s, th350 and built 350, gets roughly 11 mpg at 60-65 mph. my motor turns a little over 2500 rpm with worn 36s (measure 34). If I keep it at 55 or less it gets as good as 13 and if I go 70+mph it drops to single digits. I had a truck that would get 15mpg on the highway but the engine was mostly stock and I had 3.08s with 33s

If you want high mpg with a gas engine I would go for a 5.3 vortech but keep the fuel injection. And drop tire size/change gears. Even with the correct gears larger tires are harder to turn.

 

[4xcrazy]

'05 Avalanche, 5.3ltr, 75mph at about 2200 rpm. Truck likes to run as well. :-)