My 95 Cummins Expedition project

[bloodyWEST]

oh ok, it raises the axle side, that makes a lot more sense. thanks for going to that trouble for me.

Have you played with your P-pump at all? GSK? my 34" tires and 4.10 gears make my truck really spin some rpms on the highway, my cummins guru friend says a 3000 GSK will move my fuel curve up and help the "flat" feeling i get when rev'd out at 2200rpms on the freeway.

how is your power/cruise rpm with the 3.55s on the hwy?

 

[Darwin]

my 34" tires and 4.10 gears make my truck really spin some rpms on the highway,

I have 3.55's if you want to trade straight up. I desperately want 4.10's but I do not want to fork out the cash it would cost to change over.

my cummins guru friend says a 3000 GSK will move my fuel curve up and help the "flat" feeling i get when rev'd out at 2200rpms on the freeway.

I would keep the 4k springs. you should be getting fuel all the way up to 3,800 rpm, so if you are getting a "flat" feeling the gov. springs I do not think would be the culprit. I could be wrong. 3k springs will only fuel to around 2,800 rpms.

 

[Darwin]

What size offset/backspace are those 8 bolt rims?

 

[CumminAlong]

oh ok, it raises the axle side, that makes a lot more sense. thanks for going to that trouble for me.

Have you played with your P-pump at all? GSK? my 34" tires and 4.10 gears make my truck really spin some rpms on the highway, my cummins guru friend says a 3000 GSK will move my fuel curve up and help the "flat" feeling i get when rev'd out at 2200rpms on the freeway.

how is your power/cruise rpm with the 3.55s on the hwy?

I've put a 195 plate in my 175 pump, and all the way up. Turned up the star wheel a turn or so. That's all, and I like it. Not much smoke, and better power. Wastegate is plugged and I pull about 26PSI. I'd love a GSK in my rig, that's next on the list along with injectors and a #11 plate. It was perfect at about 2000rpm at 70mph. I cruised at about 66-68 mostly and it was great. Great mileage, cool EGTs. Now it sucks on the highway. Can barely tap 5th.

I have 3.55's if you want to trade straight up. I desperately want 4.10's but I do not want to fork out the cash it would cost to change over.


I would keep the 4k springs. you should be getting fuel all the way up to 3,800 rpm, so if you are getting a "flat" feeling the gov. springs I do not think would be the culprit. I could be wrong. 3k springs will only fuel to around 2,800 rpms.

I need 4.10s as well. Badly.

What size offset/backspace are those 8 bolt rims?

3.5" backspacing.

 

[bloodyWEST]

I have 3.55's if you want to trade straight up. I desperately want 4.10's but I do not want to fork out the cash it would cost to change over.


I would keep the 4k springs. you should be getting fuel all the way up to 3,800 rpm, so if you are getting a "flat" feeling the gov. springs I do not think would be the culprit. I could be wrong. 3k springs will only fuel to around 2,800 rpms.

:drool: my sled pulling friend already tried to talk me into that, ill keep them thanks. oh yea, and he sheared his rear pinion off in Hollister last week

i have the factory governor spring now. thanks guys

 

[Metcalf]

I'm surprised you have that many problems with your 3.55/37 combo.

I've been running 3.55's with 39's for years. Would 3.73's or 4.10's be better, sure, but I have tens of thousands of miles on the combo. I only use 5th above about 65mph and start in 1st, but in general it really doesn't seem THAT picky. My motor is the earlier rotary pump version, and basically stock however....just afc tuning and the deep side on the fuel cone.

Scrounging a set of 4.10 low pinion D60 gears for the front would be easy. Just about any late 70s and early 80s ford truck with a D60 rear will have them. In the rear, you would probably have to do some digging, but 4.10 Dana 80 gears are in a lot of junkyards these days in your style dodge truck...

nice project!

 

[CumminAlong]

I'm surprised you have that many problems with your 3.55/37 combo.

I've been running 3.55's with 39's for years. Would 3.73's or 4.10's be better, sure, but I have tens of thousands of miles on the combo. I only use 5th above about 65mph and start in 1st, but in general it really doesn't seem THAT picky. My motor is the earlier rotary pump version, and basically stock however....just afc tuning and the deep side on the fuel cone.

Scrounging a set of 4.10 low pinion D60 gears for the front would be easy. Just about any late 70s and early 80s ford truck with a D60 rear will have them. In the rear, you would probably have to do some digging, but 4.10 Dana 80 gears are in a lot of junkyards these days in your style dodge truck...

nice project!

Thanks for the input. Yeah, I guess I'm just used to lower geared Cummins trucks. I've had numerous 5spd's with 3.55s and 4.10s and the 12 valve just seems to like it better. I am ordering some 4.10s today, just going to get new gears and install kits. One thing to note (I don't know if it applies to you or not) is for me to regear to 4.10s in the rear with my 3.73 & down carrier, I need a "thick" ring gear.
http://www.xtremediesel.com/yukonringandpiniongearsetfordanaspicer80ina411ratiothickgear.aspx

 

[Metcalf]

A little late now, but it's also possible to use D70 gears in a D60 housing now with the proper carrier and install kit.....

 

[CumminAlong]

True. But then I need a different carrier.
4.10s and install kits are ordered!

 

[CumminAlong]

Did a little work on the Dodge today, got the wheel wells cut -- no more tire rub!

I will weld some sheet metal plates over the "holes" next weekend. Shame I don't have more time to work on this truck.

Also, I scored a "new" tailgate off CL for $200, so now my camper shell closes correctly.