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Discussion Starter #1
Hey there 4btswap members.

New to this forum and to 4bts in general. I've worked on 24 valve cummins and fell in love with the motor. I recently purchased a 1948 Power Wagon and the 230 flat head just isnt doing it (max speed around 30 mph) . I'm set on putting a 4bt in, but would like some more knowledge before I pull the trigger on which motor I should purchase. Mahalos for having me here 馃馃
 

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There is a company here in North Carolina that specializes in Cummins repowers on the Power Wagons. Here's a link to their site. https://www.mseriesrebuild.com/ They use the P pump 4bt in some swaps and possibly the ISBe units as well. Things you have to consider are changing transmission and possibly differential gears. The old Power Wagons were not highway cruisers. They were geared very low for crawling around in places most vehicles couldn't go.
 

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There are Power Wagon guys somewhere, there are higher ratio gears available, those conversion guys in NC probably have the contact info.

Ed
 

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Discussion Starter #4
Thanks for your guys replies. Yah, the gearing in the truck is extremely high. I'm still not sure if Ill be changing it to 4.89 or 4.30 but I do have a line up to both of them. As far as the transmission, I'm still debating if I want to do a np4500 or keep the stock one. I guess I enjoy pulling my hair out trying to shift n stuff. I want to keep the interior as vintage as possible with the sticks on the floor.
I'll reach out to the NC company for some advise either way. Thank you for the link. Haven't heard of them
 

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The direct original trans. will soon become tiring, a 4500 OD trans will soon let you cruise at a more normal speed. Since transfer case is divorced, might want to consider modern to handle the torque. Original gears are something like 5.89!

Ed
 

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Another transmission that might be considered is the military Spicer 3053A. It's a 5 speed with a .85 OD 5th gear. Sort of similar to the OEM transmission in Power Wagon. It uses an SAE3 bellhousing adapter. Your 1948 model is in the 1st series of the trucks that was built during WWII. Model is listed a a B-1-PW. Differential gear ratio in your truck should be 5.83. There was a 4.89 gear for 1/2 ton models. Not sure if there is any higher ratio for those old axles.
 

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Discussion Starter #7
Yah, the stock gearing was 5.89s which is what's still in the truck. There's a Company who makes 4.89 and 4.30 gearing for these axles.
My biggest concern is wanting to keep the inside as stock as possible. At first I was thinking of buying a nv4500 but I'll have to find out some stuff (if I change the trans). I just liked the fact that the trans is proven strong and that it's been done before so I know it can work. I'm just not sure how much fabrication to the interior I'll have to do.
Being I live in hawaii really limits my options as far as outsourcing anything. But right now I'm here to learn and figure out which n path I want to take. I'll be sure to ask you guys for opinions and any questions I have on these things. I haven't ever done a build like this before so it's gonna be a huge learning process for me
 

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I went the hard route of using the ISB170e (common rail computerised 3.9). I swapped out the axles to 4.10 1 ton GM with disc brakes. I also used the NV4500HD 5 speed OD. I mated that to an NP205 Xfer Case (1993 Dodge is only year that fits as far as I know). I don't recommend anyone following in my footsteps. A 4BTA is probably the simplest path forward. You are still going to need new drivelines, new motor and transmission mounts, and a ton of fabrications. You will need a high level of financial and personal commitment to make any conversion like this happen. Far easier might be to keep it stick except for axles. By the time you pay for brake and gear changes, you are into acset of newer 4.10 axles. That is the key to the highway. Those 4.89s aren't going to be enough. If memory serves me, a 318 V8 might bolt up to that factory tranny. Even a "Little Red Wagon" Hemi which is what I would have done next. A 225 slant six might even bolt up. If you want a real head turner, put in a Hemi straight 6 from Australia. That would be awesome. Good luck, whatever way you go. Gene
 

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Backwards thinking (possibly)

Thanks for your guys replies. Yah, the gearing in the truck is extremely high. I'm still not sure if Ill be changing it to 4.89 or 4.30 but I do have a line up to both of them. As far as the transmission, I'm still debating if I want to do a np4500 or keep the stock one. I guess I enjoy pulling my hair out trying to shift n stuff. I want to keep the interior as vintage as possible with the sticks on the floor.
I'll reach out to the NC company for some advise either way. Thank you for the link. Haven't heard of them
The higher the # the slower the gearing 4.89 is slower than 4.3 etc
I once owned a 1967 Chevy pu differential gears 4.56 , 750/16 tires , 75 mph was close to 5000 rpm!
Go as high as you can for road use + od trans
 

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Discussion Starter #12
Hey climber. You got any pics of the inside? I wanna see the amount of fabrication needed on the floor to put in the nv4500. I know it'll be a financial burden but want to keep that stock axles for some reason. Even thought with the money involved I could probably just put some bad ass Rockwell axles on
 

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Discussion Starter #14
As far as the gearing I usually run 4.10s on my other trucks which works well on 35/37s. This truck will see a lot of road but not to much highway. The fastest speed limit we have here is 55mph and in town is between 25 and 35. Even our main roads in town is 35mph.
 

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? Is the 5035a an auto or stick? As pointed out on other threads you want rpm to run in the range of 1800-2000 rpm, even when out in the middle of nowhere, when you get to 55 shift into over-drive & get on down the road 锟斤拷
Confused, " 1948 first production ww2" ?? My dad came home Sept 1945 when I (4&1/2 yrs old)saw the car & its driver pull up in front of our house I ran inside, told mom DADDY IS HOME !!
Confusion clears up reread post #6 , had missed the little word "in" , like in the series of.
 
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