Truck/Towing question?

[dzg]

After alot of thought and consideration i have decided to keep my current tow rig (77F250) rather then spend tons of money on something different.

For the last two years i have "put up" with the crazy high rear end ratio (3.07) while lugging around my 7000 lb camper.

This spring the hunt will be on for either a 3.73 or 4.10 (prefer posi) rear end to replace the current one.

My question is, what would be better? 3.73s or 4.10s? Its going to get used for more then towing, but mpgs arnt a top priority.

I know this us the wrong site to ask on, but im curious on your guys ol
pinions. Thanks in advance.

[countrycummins99]

if you in the mountains the 4:10 are your best bet if its flat land the 3;73 will be fine I have 3:55 in my truck and with the mountains around here I wish it was 4:10s

[fmints]

I have 3.55's in my truck and it get around just find but 3.73's are better. 4.10's will bring down a house and be killer on the mpg that you aren't really worried with, so I'll go with the 3.73's.

[ARGOJIM]

I don't know how you got 3.07's but most people would kill for that for mpg, 4.10's are best for the hills worst for the mpg (probably 6 to 7 with 33's) , 3.73's are a better choice at about 8 to 9, 3.54's should get you 10 or so.
If your truck is a 4 speed switching to the 3.54's and a 5 speed(4 speed overdrive) should give you 12 or so. A gearvender od unit will work with the 4 speed or C6 and help with fuel milage on any combo.

[riotwarrior]

91 F350 4x 7.3 IDI, 5sp ZF, 4.10 255/85/16 Toyo M55 tyres

19 mpg consistently

14-16 towing heavy 6k

to the OP, you must have a Dana 61 diff I presume seeing your gearing.

have you considered a swap to a zf five sp and say 3.55 or even 3.73 best of both worlds then...

[dzg]

I do get good mileage running empty with the 3.07s (around 13 average).

The truck is a 2wd, with a C6 and 400 V8. It does ok with the 3.07s but i get sick of being floored in 2nd on any kinda hill trying to keep 45.

It is a Dana 61 rear.

One more question, according to car part.com there is a difference between the camper special (which mine is) and regular F250 rears in that era, anybody know if theyll interchange?

thanks for the input!