90 4X4, rebuilt 302 with some "high performance parts." I didn't do the rebuild and neither did the guy I bought it from.

My mechanic said it has an oversized cam, high performance distributor from what he could tell. I changed the distributor cap and rotor this week.

Mileage has always been 10.5. I'm hopeful that the new gears in the front, new rebuilt axles in front, replaced wheel bearings, will help.

Planning on new wires and plugs soon. Truck has a camper shell.

 

94 from my sig . Been averaging 15.3 last 3 week and that is with morning deice sessions.

96 F150 5.8 10-12 MPG with e40d 4x4 and 3:55 rears. You know the typical 351.

 

1995 F-150 4x4, 5.0L, 4R70W, Regular Cab/Long Bed, 3.31's, 32x11.50's - 11-13 MPG

-Rod

 

1991 F150 4.9L, ZF5, 3.08, 31" tires, gets about 17-18 all the time, it doesn't seem to care if it is city or highway.

 

1994 F-150 Single Cab
302
Ravin Exhaust
K&N filter

I regularly run Seafoam and if I drive like a grandpa I can get around 14.5 mpg.

 

31 inch tires and 3.08 ratio with overdrive?? What kind of RPMs are you pulling at 60 MPH--1600??

 

that would put him right in the torque band for an I6

 

Yeah, about. The 300 likes a tall gear. I used to have 3.55 and the 3.08 works better with the six. Makes my 4th gear more useable. I still start out in 2nd on the ZF with no prob.

 

my old 92 f150 reg cab/long bed 4x4 with 302, aod, 32x11.50x15 mud terrains, long tube headers and true duals never once averaged over 9.6mpg, city or high way.

my new 89 250 hd reg cab long bed 4x4 351 c6 33x12.50,16.5 all terrains, stock manifolds and true duals... well dont know yet. still working out vaccum lines and and other little quirks trying to get it running right. not looking forward to the mileage it's going to be getting

 

I have the same setup as Rikard, same mileage too, but I found I get better mileage at highway speeds 80 + kmh.
It's the 3.55 gears that cause the lack of good mileage.

 

It's not about stress levels, but rather engine efficiency and total system loss.

 

96 302 auto w/ 355 gears, I avg. 16 mixed use with 265 tires, Lets see what happens next week when the 33s go on.

 

96' F350 Crewcab 4x4 5.8L E4OD, steel diamond plate bedliner, figure weighs about 200lbs?, 235/245 tires.

Guessing around 12mpg. Neither tank reads, and my driving is varied enough that I don't bother to check. I figure 12mpg is a base.

I need new tires, thinking of going slightly bigger to bring down the rear end ratio some.

Looking to do full headers and custom single exhaust when I'm done installing my new carport and can work under it. Next couple months.

 

You are right about that--that 4.9 sure does pull from off idle. It is a very well developed truck engine. Too bad the straight six gas engine isnt in style anymore amoung the present day engineers

 

What do you call it--volumetric efficiency?? The total volume of the cylinder that gets filled on each downstoke. And I suspect that thermal efficiency is a factor also.

What did I read--33 percent of the energy goes out the exhaust as heat and another 33 percent gets into the cooling system as heat and only 33 percent of the total energy gets to the crankshaft--in a typical 4 stroke gasoline engine .