1997 Superduty
Elder User
Joined: Dec 2003
Posts: 610
Likes: 0
From: socal
I have two of the F-Supers. They are great trucks for what I do but yeah 2000+ RPM above 60 MPH really drinks the fuel. I try hard to stay at 55/1800 and can avg. 14mpg but man it's tough to do.
5.13 is the gasser ratio diesel is 4.63. Is it possible someone swapped in a junkyard rear end?
I plan on swapping to 3.73 that is by far the easiest option and most cost effective I think. I can avg 16 mpg and cruise at 65 with 3.73 and still get reasonable performance when loaded. I spoke to a guy who went 3.55 on his (5 spd) and he said it was too high wished he went 4.10 or 3.73.
5.13 is the gasser ratio diesel is 4.63. Is it possible someone swapped in a junkyard rear end?
I plan on swapping to 3.73 that is by far the easiest option and most cost effective I think. I can avg 16 mpg and cruise at 65 with 3.73 and still get reasonable performance when loaded. I spoke to a guy who went 3.55 on his (5 spd) and he said it was too high wished he went 4.10 or 3.73.
Hotshot
Joined: Dec 2006
Posts: 14,069
Likes: 17
From: Melbourne, Ky
Yes they are. They made them that way from sometime around 1990 till 1997. They are basically the same thing as an F450. They called them F-SuperDuty instead of F450's. They are around 14,000 to 16,000 pound rated vehicles. I wonder how much it affects their weight rating by installing a higher gear ratio? More stress for sure will be experienced all along the driveline. That wouldn't make much difference driving around empty, but put a load on it, or hook to something.
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