Seeking taller final gear ratio

I am leaning towards making room for 235/85s by moving the front axle forwards. Might having to get new front leaf springs be an opportunity? My rig has a ride like a deuce and a half. With its two solid axles it bangs over expansion joints and road divots.
Any thoughts on how to make a softer ride? Do aftermarket set ups, with their talk of "five point articulation" and coil over shocks in addition to leaf springs, make a difference that is worth the cost?
I figure I could install air bags, to stiffen the ride when I tow, if I went with softer leaf springs.

So 235/85s aren't stock for a one-ton van? Sorry, my bad; had my base facts wrong. One "compromise" size that might fit is 215/85; IIRC that's the stock size for the dually pickups.

Newer dodge drops on driver side. My brothers ram has 3.42's. It's drivers side drop but I don't know if it's reverse rotation or not. Do super dutys have other options?

Personally I would like to see you do 37" tires on the thing. My centurion has 4.10 and 37's, that thing is a monster getting rolling! Lift it! It's the equivalent to 3.55 and standard size tires... Just sexier.

Front axle swap to a standard rotation axle, like the Dodge, for more gear sets.. a tcase adapter is needed for the C6/Chevy np205 but hey whatever. Ford d61's didn't exist, overdrive transmissions were pioneered for these rigs so 3.55 is the highest ratio for d60 reverse rotation. My dad's 83? F150 with a d44 had 3.08 AND a Clark 3+od top loader! We towed all sortsa heavy crap(not far! Dangerous to say the least) with that thing! I love inline 6 power...

Overdrive trans. E4od's will work... Even on carbureted engines with a simple computer, saw it on that there pirate off roading forum! E4od swap to keep you from punching holes in the floor OR the super awesome zf5 swap and gain a super low 1st and overdrive.

3 options for ya to get some lower rpm. As I always put out... Do a 2005+ d60 swap. Coil springs and a tighter turn radius are so nice!

Well, I finally decided to get bigger tires, and make room for them by trimming away the rear of the front fender wells as well as the front tips of my running boards. I had to get spacers as well, both to keep the inner tires of my dualies off the leaf spring anchor plate as well as keep the dualie tires from touching each other.

Old Tires:
Hercules Terra Trac AT ll 215/85 R16 E
Tread width 8.4 in
Overall diameter 30.31 in

New
Same - 285/75 R16 E
Tread width 11.50
Diameter 32.60 in

Overall I like the change. My seat of the pants appreciation of driving my rig has improved. Noticeably less RPM and roaring now at highway speed.

1989 Ford E 350 / Born Free "President" / 7.3 IDIT (Hypermax) / C6 / NP205 / GVOD / 3.54 diffs / 32.60 inch diameter tires.

IIRC D60, 61, and 70 all share the same carrier

For sound deading I also stuffed pieces of insulation all throughout the dash and in front of the pedals where ever it would fit and not interfere woth functuonality. I used the recycled denim insulation that they sell for walls at home improvement stores. It is supposed to have superior sound deading qualities and I also dont like the idea of fiberglass possibly flying around in the cab.

I have looked into swapping my c6 to an e4od. If time and $ didn't matter I would have already done it. I can keep my 3.54s and have double OD with my DNE2. Even if I swapped to 4.10s I would still have a lower cruising rpm than I currently have with my 3.54/c6/DNE2 combo.

A couple tricks to fine tune your lift or axle position....

http://offroaddesign.com/catalog/Zero Rates.htm
http://offroaddesign.com/catalog/Axle Offset Plates.html

kuskoal said:

3.55 is the highest ratio for d60 reverse rotation.

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There is 3.31 in some 6.7L powerstroke trucks.

jwalterus said:

IIRC D60, 61, and 70 all share the same carrier

Click to expand...

No, the 70 has a larger ring gear bolt pattern. BTDT.

If we're just talking about the differential's innards... Dana 60 and 70 powr-lok share parts; so do Dana 70 and 80 open diffs.

If the Dana 61 works like the Dodge Dana '71', then the carrier probably standard, and the offset is built into the housing.