IDI in Half Ton: MPG & Suspension

[1800joedaddy]

Napa carries the U-joint to mate the drive shaft to 8.8 yoke.
#459 precision.

 

[Pino2234]

Trapper,

You make any progress on your build?

 

[bobbywalter]

over 25 mpg with a 6.9 is very impressive. was that at 65 mph or faster?

 

[S-west]

Did you figure out the suspension? I'm putting a 7.3 in my 69 f100 4x4 with coils and I was told I have to have custom springs made.

 

[rjjp]

You won't get 20. That being said, I have 33s and 3.5 gears with a NP435 4spd. I am not quite sure what it is gettting now, but prior to my rebuild, I was at 18. If you beat on it at lower RPMs, its easier on the fuel than at higher RPMs. Like spinning the tires off the line and such. But go 65 and hammer it to get to 75 and it sucks the fuel. It takes a ton of HP to make 10mph over 50.

With that, I had a donor for my bronco. I snagged the 250 springs out of the 2wd and it raised the front end up higher than the rear end. Not a lot, but it is higher. Now, the camber is out at the top. Not bad, but it is starting to show after I drive it (inside lugs are all dusty). The tranny came out of a 76 (I think) highboy and the rest of the drivetrain is factory 84 fresh.

Ripped off the rear bumper pulling out a tree, but that was because the welds had rusted to the point that there was more surface area of a penny than weld on the driver's side. As long as rust is not a problem and bolts/bushings are in good working order, you should be okay.

Since my tach does not work, I do not know what my RPMs are at speed, but I KNOW an overdrive would do me some good.

SWS

Why not? I can get over 20 with 4.10s in a F250, a F150 with 3.08 or 3.55 should be able to do better.

 

[ocnorb]

^^^^^ +1... I get 17-18 with a crew cab dually. Can't imagine a lighter vehicle doing worse.

 

[DeepRoots]

If mpg is the game plan and a c6 is required, you *can* make a partial roller for very little real money.
make sure the front end is right or you'll be saving money on fuel only to spend it on tires.

good luck, it is a noble project I wanted to take on myself.... of course my hopped up 390fe was addictive, so I'm living with 7mpg, but it's fun

 

[bab029]

^^^^^ +1... I get 17-18 with a crew cab dually. Can't imagine a lighter vehicle doing worse.

I regularly see 20 in a SCLB e4od with 4.10s. Mixed driving...