V8 and Ranger Overdrive questions

[Greg Coffin]

For many years I have quietly planned a Power Wagon 6x6 project. The latest plan had been to use a Cummins 4BT engine, Ranger Overdrive, NP435 or SM465, 5.83 gears, and 9.00-16 tires, with a WM300 cab and 9ft bed. It would not have a winch.

Last week I re-examined the plan and some of my long-held assumptions about the truck. Given the expense of a 4BT, the fact that this truck won't be run as a daily driver and will likely remain a pavement queen, I have decided to use a small block V8 instead of the 4BT.

This new change of direction raises a few questions that need answers:
1) Will a Ranger Overdrive fit behind a small block V8 without moving the NP200?
2) Do the small block engines need a Ranger Overdrive, given their greater RPM flexibility vs the 4BT?
3) I am leaning toward a 318/360 V8, but are there compelling reasons to use a small block Chevy instead?

I'm aware that a Ranger for Dodge will be more expensive than for a Chevy, and that's okay. I'm also prepared to us an electric radiator fan if it helps fit the V8/Ranger combo into the truck.

The move towards a V8 engine is a big departure from what I had originally planned, so I'm looking for any feedback you may have. The archives have been a great help in answering some of my new questions, but it's clear to me that things have changed quite a lot from what it was 10-15 years ago.

I have many more questions regarding power plans, drive trains, and chassis fitting, but I'll start with this for now.

Thanks much,
Greg Coffin

[maineSS]

An overdrive will definitely help fuel consumption, especially with 5:83's. The problem with the Ranger is that you'll be overdriving the t-case gearing along with the diff. If you stay with the NP 200, it needs to be in tiptop shape with respect to bearings, gears and seals to avoid overheating. A good synthetic can really help if you can keep it in the case.

If you are planning on running a centered rear diff on your 1st axle, you can convert the 200 to center drive, or use the NP 202 or 205 t-case to cut down the amount of power transmitting gears. This will also help combat heat generation.
Promoting the SBC never fails to galvanize the "All Dodge, All the Time" faction here, but the fact of the matter is that it has by far the greatest aftermarket support and parts availability of any smallblock, and can be built to a great many custom requirements. It also requires no irreversible frame hacking to make it fit, and has the greatest options for transmission adapters/bellhousings available. It all adds up to time and money to spend on other areas of the build. There is an article at www.dodgepowerwagon.com/glovebox/oday.html that may prove useful.

If you need to use an electric fan, keep in mind their limitations. They can't equal the airmoving ability of a mechanical fan, and need a more open rad (probably a custom aluminum one in your case) for heavy duty apllications. I used a twin set from a Chrysler Concord behind an OEM clutch fan rad in my Monte SS with the factory 305 V8, and would see temps spike on hot summer days when waiting at stoplights. I had a switch to turn both fans on high for that eventuality. The starting surge for both fans on low was around 60 Amps, and about 115 Amps on high, so your wiring has to be able to handle those momentary loads.

[cerial]

I plan on doing something similar running a 370 lb at 2200 350 to a 2wd sm465 in a 67 wdx.

I plan on running a 3 speed brownie box with .72 overdrive behind my 201. They used these in 1-3 ton gravel trucks with the 350/465 combo so they are plenty strong. A brownie will keep the 201 in the stock location. I plan on using the pto shifter location for the brownie shifter for the Medium(1/1), and High(.72/1) ranges. The low range is 3/1 and I see no need for it with the 465's first gear and the 5.83 gears in the axles.
The overdrive will only work in 2wd but will let me keep the low gearing that I will need for towing. This also lets me keep the option of switching back to 100% stock with little modifying.

I bought mine completly rebuilt with 2,000 miles on it for $800 from Texas. They are out there and can be found easily. If you look long enough you will find one. They are rated higher then any other overdrive unit (behind the transmission) out there currently and at only around 10"wide by 12" long it will fit without any cutting.
The simplistic slide shifter design means as long as you keep oil in the brownie it will work. No foreign made housing or cheap electronics to go bad made a brown lipe 3 speed a easy choice for me. I can not preach enough how great these little boxes are compared to the junk out there now.