Hi i have one question. I just put in my order for a DARK BLUE PEARL 07 E350 XLT 6.0L 5-SPD Van. I want to get the best mileage i can. So, will i take a big hit on the 4.10 LSlip i have on order, over the 3.55 option with out LSlip? How much more RPM can i save and MPG is it going to make 1-2-3-0? I have 6-8 days to make a change. Thanks for any help. Doug

 

Waht are you going to be using the van for. If you're going to be carrying/hauling more than 10,000 lbs on a regular basis, you'll probably want the 4.10's.

 

I won't be pulling more than 1,000 lb just race karts & long trips hunting, fishing.

 

Then you're probably better off with the 3.55 mpg-wise, but I would get an LSD rear end if I were to go off a paved road, however little that may be.

BTW, I'd inquire about these in the van forum -- you should get more authoritative answers there.