1970 F250 4x4 Cummins Conversion Build Thread - Lots of Pics!
 

Let the journey begin! This started as a “budget” project, but we all know how that goes. :eek:

Picked up a 1970 F250 4x4 for $1200. It took the 300 mile drive home with no problems!

Attachment 235108

Plans for the build:

Suspension (10” Lift)
Front: 6.5” Pro Comp Super Duty lift springs with 4” custom drop hanger
Rear: 64” Chevy rear springs with shackle flip
Wheel base shortened

Axles
Dana 60 front from a 1979 F350
14 bolt rear

Tires
41.5” Pitbull Rocker Radials

Drivetrain
1994-1998.5 Cummins
NV4500 5 speed transmission
NP205 Transfer Case

AND MUCH MUCH MORE!:-X22

Dana 60 Front is in the House!
Attachment 235109

These gears are coming out and a detroit air locker is going in!
Attachment 235110

Picked up this axle for $2700. It had been completely rebuilt but the guy went a different direction with his project. High steer arms already installed.
Attachment 235111

Attachment 235112

Interior is stripped. What do you think of the bull bar? Picked it up at a local auto parts store for $75. It is for a cherokee... but will work nicely on this truck.
Attachment 235113

Truck is naked :D
Attachment 235114

Attachment 235115

Attachment 235116

Attachment 235117

Well we will see how this project goes. The only thing stopping me now is the almighty dollar :-X15

Freaking awesome, keep us posted

Subscribed great build you will be doing exactly what I'm in the middle of doing on my 71 crew cab 8" super duty springs front and rear Dana 60 front Dana 80 or sterling rear custom drop front crossmember cummins and nv4500 got the front suspension on now I'm getting ready to drop the cummins and nv4500 in so I can put in and level up the rear suspension keep the pics coming

Neat project so far. Subscribed !

Nice!
 

Looks good to me. Subscribed.

Good to see another diesel bump. Looks like a nice start and a nice project.

cummins + ford. doesnt get any better than that.

This is what happens when you try to do a BIG job with little tools :-lamesign

Attachment 235118

Attachment 235119

But luckily I have cool neighbors with BIG toys! Went ahead and pulled the motor at the same time.

Attachment 235120

Attachment 235121

Let the gutless gas hog say hello to ebay!

Attachment 235122

Everything is back to normal :-X22

Attachment 235123

That sucks same thing happen to me with my crew cab was stripped down like yours was except mine already had the motor out when it fell it was hell trying to lift it back up when I only had 1 jack to use to lift it back up

Working on 69 crew
 

Looks awesome so far. I'm not interested in all of that sky, but they do look awesome. I'll follow and see how it goes. I've got a long way to go with mine and yep it is the almighty dollar that gets in the way.

I'm also looking to drop a early 12V 6BT Cummins in a '68 F250 4x4 Crew... not sure to buy a new crate motor or donor truck. Looking forward to your progress.

if i were you hivewax i would get a donor truck i did this on a superduty and am now doing a 72 crew the donor is the way to go it still will be aroud 6000.00 to 15000.00 to do the swap depending on what you do.

smitty3215 has the right idea. Buy a entire doner truck. That way you can pull everything you may need including fan, radiator, alternator, ac compressor, etc. If you get a truck with the transmission you want also, then that will save you money adapting things. Once you have taken everything you want off the truck, part out the rest and scrap the metal. If you play your cards right, you will have a conversion set up for not that much $$$.

I am still working on finding a doner truck myself. I let a 1996 with 150K miles and a 5 speed slip away a month or so ago. OOops! Spent my money on the axle :-huh Now I have to build up the piggy bank again.

budget
 

I'm shooting for 6000 on mine if i stay on budget. I'm sure it will end closer to 7k. I've got 3k in it right now.

great build keep the pics commin

Did some heavy lifting today :-whud

Attachment 235124

Attachment 235125

Attachment 235126

Attachment 235127

:-X01 Audios four speed!

Attachment 235128

The Dana 24 transfer case isn't going to cut it. I will be picking up a divorced NP 205 from a 1973-1977 Ford in the next few months. Luckily the pick and pulls that I frequent don't have a shortage of these old Ford trucks. The divorced NP 205 should be easy to connect to the Dodge trans to keep things simple. It almost looks like the stock cross member from the Dana 24 will bolt right to the NP 205. I guess I will find out here shortly.

Attachment 235129

Attachment 235130

Frame is naked and ready to be scraped and blasted. I will probably blast it with a pressure steamer and coat it with some frame paint from eastwood.

Attachment 235131

I got a quote from the line-x guy to spray the interior of the truck (firewall, floor, halfway up the rear). He quoted me $400 to do the job. I also talked to the Rinoliner guy but he quoted me $600 for the same job. I guess I know where I am going.

I also got the 14 bolt rear axle. I should be doing a tutorial on rebuilding the 14 bolt axle here shortly. A guy that lives down the street is a 4x4 axle specialist and is going to walk me through the process.

I am still working on a donner Dodge. I have my eyes on one, but we will see how that works out. I sold the 360 today for a $100. Audios you gutless gas hog!:-X04

Looking good everythings in about the stage of being prepped and painted as to the NP205 it is a direct bolt in for the Dana 24 t case keep pics and info coming

I decided to bring out the BIG guns to get this project moving forward :-X06

Attachment 235132

Picked up a 14 bolt axle for $100. Tore her down and documented some of the more critical steps in the process. If you are looking for detailed instructions on how to rebuild a 14 bolt axle, there is a great tutorial at:

http://www.pirate4x4.com/tech/billav...4b_Gear_Setup/

Attachment 235133

Make sure and mark the caps before you pull them off. I punch two punches on one cap and then the case, and repeat with three on the other side to differentiate between the two. Very important that they don't get switched.

Attachment 235134

Carrier assembly removed.

Attachment 235135

With hubs, axles, and carrier removed - it is time to press out the bearings and get everything cleaned up. It is best to use a long pry bar with the hubs in a vice to get the seals out - they are nasty. Remove the snap ring retainer on the bearings and press them out. You can nock the races out with a mini sledge and a long striking tube. I like to save the bearings and races until I am done building the axle in case I need the numbers off of them.

Attachment 235136

Use a puller to remove the bearings on the carrier assembly. I cut off the outer section of the bearing so that my puller could more easily mount to the remaining section. These bearings can be tough to pull off. If you put a good load on the puller and the bearing isn't moving, add a little heat to the bearing and it will be persuaded to give.

Attachment 235137

Attachment 235138

Before removing the ring gear, make sure to mark the original location so that everything goes back together the same way.

Attachment 235139

Use a mini sledge and a long striking tube to knock the ring gear loose. After this I pried the remaining section of the carrier assembly apart and removed the spider gears.

Attachment 235140

Everything is now disassembled and ready to get steamed.

Before steaming :(

Attachment 235141

After steaming :-X03

Attachment 235142

Now it is time to decide what gear ratio to go with. There are several factors that will determine this. Since I am going to be running a cummins, my cruising RPM will be lower than a standard gas engine. I read in some other forums and guys were saying that ideally they try to run 1500 RPM at 65 MPH. My target Tire size is 40". I want to be able to bump things up to a 42" or down to a 38" tire if need be in the future.

Any suggestions on gear ratio for my application? Does anyone know of a spot where there is a good gear ratio tire size chart for the cummins? I want to be able to cruz 75 MPH comfortably without compromising the trucks off road capability. I know, I know... everyone wants the best of both worlds :-dancing1

I like this one: RPM / Speed / Gear Ratio Visual Calc

I had a hard time getting that calculator to work for my application, but I did find this one:

Gear Ratio Calculator

Good Stuff! This calculator lets you input the exact transmission and transferase separately so you get all the specific info you need for your application at any RPM or MPH.

Looks like 4.88 is going to be the ticket. I plugged in my info and then matched it up to a couple of stock cummins RPM cycles on youtube.

A saw zaw makes quick work of the body mounts :-duel1

Attachment 235143

I HATE RIVETS! Who doesn't though?

I removed the rivets by grinding off the head, then drilling the center so that I could get a punch to line up nicely. I have used a air hammer in the past and it worked well, but it broke, so back to the old fashioned way. Most came out relatively easy, but a couple were pretty stubborn. Lesson learned: don't use a sledge hammer (mini sledge is better) because it can actually start pushing in the metal on the frame with the rivet if it is being stubborn. :-banghead Oh well, I will just have to brace it and make it stronger :-X06

Attachment 235144

Attachment 235145

Found some more help :)

Attachment 235146

Spent the rest of the day cleaning up the frame with a wire wheel attached to a die grinder. Almost time for the fun stuff. 8D

wow, with that many helpers and the dog supervising you're gonna be finished in a week!

I decided to cut into the front crossmember the other day to make way for the cummins oil pan. I have seen two ways of making clearance for the cummins oil pan by other FTE users.

1) The first way would be to completely relocate the front cross member toward the rear. This would allow ample space for the stock dodge AC compressor.

2) The second way would be to shorten the front cross member so that the cummins oil pan can slide over the top. This will cause clearance issues with the AC compressor.

I opted for option #2 to keep a it simple and maintain a "stock" look. I may run a AC compressor, but I am thinking that relocating the compressor on the front of the engine may be possible. I guess I will find out :eek:

Attachment 235147

Attachment 235148

Attachment 235149

Attachment 235150

Attachment 235151

Attachment 235152

I am going to leave the top piece that was cut off alone until the cummins arrives for a test fit. I should be scoring a donner dodge in a couple of weeks, but we will have to see how that works out.

:-innocent

I'll be watching how you end up doing your cross member for the cummins I cut about a foot out of the top piece on mine in the center and the cummins slid right in the A/C comp may need relocated if the cummins can't be raised enough to clear the top of the cross member right now its touching I haven't decided how I want to do mine make up a new one or possibly cut the top half off and replate it it looks like it will work if you replate it just need to buy a welder and I can start welding the mounts I'll be updating my long due build thread soon it will have pics of how the cummins sits in it now and show some clearance issues with it

Oh yea I wanted to ask why the swap of the Dana 24 for a np205

The divorced NP205 is probably one of the most popular off road transferases in use today. As a result of it's popularity, it is heavily supported by the aftermarket and parts are cheap. If I ever break something and need to replace or want to upgrade, I know that I will have a lot of options.

This is the same reason that I went with the 14 bolt rear axle over a Dana 60 or 70. I can build a fully capable rear axle with top of the line everything for about $1000 by using the 14 bolt. If I ever want to find replacement parts for the 14 bolt, I know that they will be much cheaper than the dana 60 or 70 because of the overwhelming aftermarket support.

Here are the threads for the two cross member options I mentioned above. You are probably familiar with them.

Option #1 - Build a new cross member and relocate it:

https://www.ford-trucks.com/forums/6...onversion.html

Option #2 - Modify the stock cross member and deal with AC compressor clearance issues.

https://www.ford-trucks.com/forums/7...rew-cab-3.html

I am hoping to move forward aggressively on this project over the next few months. Hopefully I will have the axles installed and engine transplanted shortly. It all depended on how things come together. :-banghead

Ok. Time to talk rear springs. I decided to go with some 64" springs out of a 1999-2010 Chevy pickup. As you can see, they dwarf the stock Ford springs. I was planning on going for the 3 leaf spring pack from the 1/2 ton pickup, but the wrecking yard ended up only having a 5 leaf spring pack from a 3/4 ton. I may decided to pull a couple of leafs out to get things more flexy. :-X04

Attachment 235153

While I was at the wrecking yard I snagged a set of front (front of the rear spring) leaf spring hangers. These came out of a 80's Chevy pickup. They will automatically add a couple of inches of lift and are way more heavy duty than the stock hangers. They bolt to both the side and bottom of the frame.

1999-2010 Chevy Leaf Springs: $45 each
80's Chevy Hanger: $35 each

Attachment 235154

After comparing the 80's Chevy hanger to the stock Ford hanger, I realized that the Chevy hanger hangs a little farther out than the Ford. I was planing on using the stock front of rear spring Ford hanger to do a shackle flip on the rear of the spring, but plans have changed since they don't match correctly with the Chevy hangers.

Solution: Pick up another set of 80's Chevy front of rear spring hangers and use them in the rear along with a shackle flip (using the Chevy shackles). This will compensate for the dip in the frame on the Ford, because I will be using the same exact hanger front and rear, but the rear will have the shackle dropping down another couple of inches that will compensate for the drop in the frame. The spring should sit nice and level. I will be gaining a ton of lift by doing this set up and may be able to ditch the stock axle block. I guess we will find out :eek:

Attachment 235155

Look at the itsy bitsy Ford hanger next to the massive 80's Chevy hanger!

Attachment 235156

I will pick up another set of hangers next week, steam everything, and start bolting things up.

Picked up another set of rear spring front hangers off of a mid 80's Chevy truck. The first wrecking yard I went to didn't want to take the time to pull another set off for me, so I went to another wrecking yard down the street from them. The other wrecking yard pulled a cleaner set for $20 less. I know where I am going from now on.

Attachment 235157

Also decided to paint my grill inserts. The plastic was cracking (as usual on these grills) so I strengthened up everything from the backside with gorilla glue and painted them with some hammered finish plastic paint. I will probably clear coat them when I paint the truck.

Before
Attachment 235158

After
Attachment 235159

A little more eye candy for you all. I decided to paint the plastic parts (like the dash bezel) with the hammered finish plastic paint.

Every dash needs some bling 8D

Attachment 235160

Here is the Kwik Wire kit :-missingt

Attachment 235161

After considering my options, I have decided to stick with the stock long bed wheel base. I was going to put a flat bed on the back (which would allow me to relocate the axle wherever I wanted), but I think I am going to stick with a stock bed. I don't want to be too red neck you know :eek:

The bed from my truck is pretty beat up, so I am going to try and find a nicer one and turn my old beat up one into a trailer using the dodge frame off of the donner truck. Hopefully the donner truck will be coming home with me next week.

I ordered the rear axle parts today and will be putting that together shortly. :-X06

Great build I can't wait to see morr

Sorry to get off track, how do you subscribe to a thread? I'm looking at adding a diesel as well.

You just did.

I just did too. :D

I mocked up the 1985 Chevy 4x4 hangers and 2002 Chevy springs to see what kind of lift this set up would provide. Here is what it looks things look like loosely put together:

Attachment 235162

Looks like this set up will give about 5" of lift over the stock set up. I was actually surprised that there was not a lot more.

Attachment 235163

Measurement with the stock set up loosely put on:

Attachment 235164

Since I am going to need a little more lift to match what I am doing up front, I am going to have to buy a pair of lift springs to raise things up a little more. I am looking at BDS part #001559 Chevy 5.5" lift springs. These are for a 1/2 ton and should still be pretty flexy. I can get two delivered for about $450.

Attachment 235165

Gas Tank Suggestions?
 

Anyone have suggestions on extra capacity gas tanks? I am ditching the in cab tank and want to install one between the frame. I was thinking about going with one from LMC:

It is a 38 gallon and I can get a brand new sending unit to go with it. It is for a 73-79 Truck, but since I am moving cross members in the rear anyway it looks like it slide right in. Runs about $260 with a new sending unit.

Other suggestions?

That tank is a bit wide since the later frame is wider. It'll take extra work to get it in there.
Also, make sure the rear springs are up to the task. A leaf spring both suspends and locates the axle, so a really flexy leaf will let the axle move under power. If you want tons of power and flex, go for a multilink with coils or coilovers. This axlewrap issue is one of the reasons for the migration from quarter-elliptical to full multilink setups in smaller rigs, besides the increase in multilink options. My personal favorite is the classic three link, but a triangulated four or a properly done five will give you much more flex.
Another intermediate option is traction bars/links, if you make them about the same length as the rear section of the driveshaft they'll work decently, but you will lose flex.
I just know that even with good springs in my F250, I'm having horrific axlewrap issues with the diesel power. Since I'm running 2wd, it's going to get bars for the time being, but the next truck will be a multilink from the ground up.

Thanks for the heads up on the 73-79 gas tank. So, basically I would have to grind down my frame to make this fit. Not a great option then. Anyone else have any solutions for a 40-50+ gallon gas tank for a 67-72 highboy? I haven't found one short of fabricating my own.

I had planned on doing a traction bar/link set up on this truck. Since this is my first 4x4 build, I am trying to keep things as simple as possible within reason. Someday it would be nice to do a 3 link on a custom frame rock crawler with a narrowed front clip, but I will save that for another day.

The goal for this truck is to strike a balance between towing, off road capability, and power/fuel economy.

i think ill be putting in a mustang fuel tank in between my rear rails where the spare tire should go from what i see it should just be a matter of moving the crossmember back some and build a frame for the gas tank to sit in. what are you doing for your engine mounts for the cummins? are you going to use the poly bushings if so what size? or what i'm trying to decide what kind of setup i want or mine im at the point now where ill be welding up some mounts looking for ideas

I can't say for sure regarding the motor mounts yet until I have the motor hanging between the frame rails and take a serious look at everything. I have seen guys do a couple of different things. Some modify the stock dodge motor mounts and others build motor mounts from scratch.

I had the same idea regarding the location of the gas tank. I am just trying to find a tank that can hold 40-50 gallons of gas. I may have to take another serious look at the 73-79 extra capacity tank from LMC.

Have you looked into the long square shaped gas tanks that run longways down the side of the truck? I don't think you will find many tanks with the capacity your wanting without hacking into the tank to make it work what about using a early mustang tank fits between frame rails doesn't have the capacity you want but maybe you can fab one in front of the other not sure if your truck is long enough or not to do that though something to think about