Need input...

[meby]

As some of you know, I am currently searching for a first gen. The ideal truck would be a 4x4 reg cab single wheel that I can transfer the body off of my 75' and put it on the donor truck. This appears to be much easier than swapping a motor and trans into the 75'. That said, I have been considering a two wheel drive in the interest of making a fuel economy machine as I don't have to have a 4x4.

The first question of the moment is this: is it possible to install 3.08s into a 3.54 or a 4.10 housing or would the entire axle have to be swapped? How available are 3.08s?


A diesel mechanic friend of mine thinks that it should be possible to get close to thirty mpg if I took a 2wd reg. cab 5spd and put 3.08s in it.

What do you guys think?

[BobS]

The Dana 3.07's in our trucks have an offset pinion which makes the housing different from the 3.54 & 4.10 versions. There is a thick gear option to put 4.10's into a 3.08 housing but as far as I know nothing is available to do it in the reverse way that you want to do.

[txs]

Yeah, they moved the pinion hole about a half an inch away from the ring gear to clear the huge pinion gear on 3.07s. the area under the gear root was getting so thin they were afraid the teeth would buckle if they cut 3.08s on a d60 or 70 gear blank.

[RumbleFish]

i kinda doubt you will see 30 mpg, but high 20's are a definite possibility. i think it would be easier to use a non-ic truck, as the ic will get pretty tight behind the 70's grille/valance panel. if you do use a 2wd, your 4wd cab already has the large hump so you are good whatever you decide. gonna get it done in time for sop?

[peobryant]

I think rbrettctd had a D250 that he swapped a 'Rag in and was getting upper 20's for mileage. He also had POD's, which I'm sure didn't help. I think it would be possible if it stayed very close to stock, and he drove like me, or an old man.

Or you could use a 727 and get 28mpg.

[slingshot]

I think 30 mpg would be easier than you think. Before I started messing with my pump, I made several trips in my 93 W250 clubcab with the cruise set at 70, to Dallas and OKC and got 30.3-30.8 ,driving back and forth to work and around town I averaged around 23 mpg.
That should be alot easier to obtain with a 2WD reg cab.

[meby]

I don't know if it will be in time for SOP. I sure hope so, though. Either way, I blocked out my calendar for Saturday, but might come Friday night as well. I reckon i'll just show up in the 75' or my tdi if I have to.

I figured that mid to high twenties were possible because my dad managed to eke out 24 mpg in his 90' 4x4 reg. cab 5spd and 3.54s a couple times and another friend gets 22 to 24 on a regular basis in his 89 2wd with a 727 and 3.07s inspite of the IP and the fuel tank having small leaks.

I've pretty much decided I don't want to use an IC. I think I'd rather set up some type of a progressive water/meth system for extra air cooling and maybe an extra pony or two. It shouldn't need more power though, as a 2wd reg. cab shouldn't weigh over 5,000 lbs and should move fairly quickly in stock form. If I wind up with an IC truck, the parts might be up for grabs.



How available are 3.07 axles?

[peobryant]

Best bet on the 3.07's would be to keep an eye on either Cummins Forum or CompD's classfields. They are pretty active. Usually Cummins Forum has quite a few trucks being parted out. That would be the place I'd start.

[meby]

I found cumminsforums, but what or where is compd classifieds?

Also, is it possible to get a locker for 3.07s?

[Philip]

meby the 3:07's use the same carrier as a 3:54. Just make sure you get the correct spline count. Most os the 3:07's seem to be a 35 spline count.

[bgilbert]

I don't know if it will be in time for SOP. I sure hope so, though. Either way, I blocked out my calendar for Saturday, but might come Friday night as well. I reckon i'll just show up in the 75' or my tdi if I have to.

I could always trailer my 91.5 to SOP for you to drive home .. Might even consider a deal/trade for your 75 ..

[meby]

Did 3.07s ever come in 4x4 first gens?

[peobryant]

Did 3.07s ever come in 4x4 first gens?

Yep, from '89 to '91 Non I/C trucks, with the 727 tranny. Of course then there are the freak trucks like Philip's.

[meby]

Did 3.07s ever come in 4x4 first gens?

Yep, from '89 to '91 Non I/C trucks, with the 727 tranny. Of course then there are the freak trucks like Philip's.

Thanks.

[peobryant]

I found cumminsforums, but what or where is compd classifieds?

Also, is it possible to get a locker for 3.07s?

I just saw this, sorry. Here is a link to the CompD classfields.

http://www.competitiondiesel.com/forums ... .php?f=169

You have to click forums, then go the the very bottom to "The Swap Meet."