Frame swaps

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by: Cobalt327, Crosley, Jon, Techinspector1
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Contents

[edit] Introduction

This subject comes up often and I originally wrote this wiki article for a rodder who wanted to improve the ride, braking and handling characteristics of his 1949 International KB2 pickup truck. Many of the points made here will apply to other frame swaps as well. This article is actually more about a front/rear frame clip swap rather than using the entire frame intact.

[edit] Using OEM components

Use OEM components when possible. The factory has well-paid engineers and mega-buck computing systems to figure everything out so that it will work well together and I like taking advantage of that, doing a frame swap or front/rear clip swap and using all the parts that I can from a donor car/truck.

The thing with using an OEM chassis is that everything is engineered to work together. What you don't want to do is decide after it's built, that you want the front lower or the rear lower, or both. Because then you may have to dink with cheesy dropped spindles or cut the front coils and change the suspension geometry from "as designed" at the factory. If you want to drop the truck "in the weeds", then use only the front and rear frame clips from the Dakota and retain the under-cab International frame section. Weld the three together at ride height and call it good.

If I were going to use the entire Dakota frame in one piece (even if I sectioned it to get the wheelbase right), I would use whatever scrap pieces of material I needed to use to graft the Dakota frame rails to the frame rail holes in the International cab.

[edit] Choosing a donor chassis

After doing a little research, I've decided that I might use a Dakota donor truck for this International KB2 project. The Gen I Dakota was made from '87 to '96 and the '91 to '96 used a 318 V8 as an option, so everything would be set up for the MOPAR "A" motor of your choice: 273, 318, 340 or 360. There will be no need to fabricate motor mounts or moving the motor to the passenger side to miss the steering or any of the other contortions usually associated with a frame/clip swap that isn't well thought out beforehand. Of course, once you have your hands on a 360, a 408 stroker kit is only a phone call away.

[edit] Chassis dimensions

I like the Gen I Dakota because of the fairly narrow track, 60.7" front and 59.5" rear. Everything got wider in the Gen II truck and may present some problems with track width with the International fenders. Well, not problems really, but the tires might stick out too far and you'd have to use different wheels with a different off-set or fender flares or some other such foolishness that can be avoided by using the narrower track Gen I components in the first place. Depending on the configuration of the Gen I Dakota, three different wheelbases were used, 112.0", 124.0" and 131.0. By the way, these trucks came with power rack and pinion steering. Another thing of interest is that these trucks came in 2WD and 4WD. So, if you wanted a 4WD International, you could certainly have it. Before removing any parts from the Dakota donor, roll it onto a scale and weigh just the front axle weight. Write it down. Now, weigh just the rear axle weight. Write it down. You will need this information later if you need to change springs.

If a guy were going to use the entire frame intact, he might get lucky and find that one of these 3 different wheelbases were exactly right. If not, use the Dakota frame that has a longer wheelbase than the body being used and section the frame between the cab and differential, then have the drive shaft shortened or order a custom drive shaft.

[edit] Track width/wheel and tire fitment

For getting the wheels/tires just right in the wheel wells for the best look, I'd jack up the International, remove the wheels and tires, then lower the body back to the ride height I wanted to use and place jack stands under the frame. I'd roll the front and rear tires forward and backward in the wheel wells until I got the "eyeball" that I wanted and measure the wheelbase between the centers of the wheels. That's the figure I would use for the final wheelbase to build the truck on.

Once I got the eyeball right, I might drop a line on a plumb bob from the center of the wheel to the ground and make a mark. Drop a line from some point on the body and make a mark. Measure between the points and write it down. Do this front and rear. Take the measurement off the CAB, not the fender or the bed. You'll need this info later to position the front and rear Dakota clips if you decide to build the truck lower than stock.

Generally speaking you don't want any part of the truck lower than 4.00" from the ground when measured at curb weight (with driver and 1/2 tank of gas), so don't go nuts with the positioning of the body. I have found that keeping a 4x4 piece of timber (built up to measure 4") handy to scoot around under the truck during the build will insure that you have sufficient ground clearance to miss most road obstacles and allow enough suspension movement to afford a good ride.

[edit] Lower than stock ride height

Here's how I might do the "lower than stock" build. With your Dakota donor truck still complete and sitting level, put an inclinometer on the lower control arms and write down the angle (assuming you're using a 2-wheel drive donor). This will insure that when the International is finished, the angle of the Dakota lower control arms will be the same as they were stock and all the suspension geometry will be stock.

Use the inclinometer on some part of the frame or spring hat or upper control arm mounting points inside the engine compartment to find the fore-aft angle of the front of the frame. (THIS IS WITH THE DAKOTA DONOR TRUCK STILL ALL TOGETHER AND SITTING SQUARE ON A LEVEL SURFACE WITH TIRE PRESSURE EQUALIZED AT MFG. SPECS). You'll need this information later when you mate the Dakota clip to the International center section to make certain the clip is on the same fore/aft attitude as stock so that you don't screw up the caster that's engineered into the front suspension. Write it down. You want to adjust the caster so that the steering wheel comes back to neutral all by itself after a turn; in order to achieve that, the clip must be installed at the same angle it was in the donor truck. If you're doing the project with just the clips that you found or purchased, find a complete, running, stock ride height Dakota that the owner will let you take some angles from, again, with the truck sitting on a level surface and tires aired up.

[edit] Front end

With the Dakota front clip cut off at the firewall and sitting loose, disassemble and remove the torsion bars and shocks. Re-assemble without the torsion bars using all-thread, washers, nuts and whatever it takes to put the all-thread in where the shocks mounted to hold the whole mess together without the torsion bars and at the control arm angle you found when you put the inclinometer on the lower control arms of the Dakota when the truck was complete. This is where you will make or break the project- getting the clip at the proper attitude and spindles positioned at the same place relative to the Dakota frame section.

Chock up the Dakota clip at the fore-aft attitude you found with the inclinometer in the engine compartment of the Dakota when it was still complete. With the International cab and center frame clip positioned at the height and attitude you want as a finished product, roll the Dakota clip into place and connect the Dakota clip to the International middle frame section. Use your gas axe to cut pieces off the Dakota/International frame clips where they interfere with each other as you roll the Dakota frame clip into position. Position the center of the front wheel of the Dakota clip relative to the International body using the dimension you wrote down when you originally dropped a line from the body. Of course, you'll want to fish-plate the connections you make at the Dakota/International frame connection to assure integrity of the graft. The resulting connection might look somewhat like a "Z" as viewed from the side. This is called Z-ing the frame.

[edit] Rear end

Same thing in the rear. Measure the top of the differential tube to the frame or frame member with the Dakota complete and sitting on level ground. Write it down. You will have to remove the springs and fabricate some contrivance to hold the differential in place at that measurement. I might use some U-bolts and scrap plate to bolt to the housing, then weld a couple of pieces of thick-wall tubing to the scrap plate, coming off the plate in a "V" to bolt or tack the other ends of the tubing to the frame of frame member. Just something to hold the differential in place relative to the frame at ride height while you position it to mate up with the rear stubs of the International frame. If I were using a 4WD donor, I'd use the same V-bar fixtures front and rear.

Of course, you'll want to measure on an "X" pattern between the front and rear Dakota clips to insure that the clips are square with each other and also square with the International center frame section before you begin welding the whole mess together. You can do this easily by dropping a plumb line down to the ground or working surface from two identical points on the front clip and two identical points on the rear clip and measuring on an "X" between the 4 points. Position the International at the ride height you want. Remove the fenders and bed. Whack off the frame rails about a foot in front of the firewall and a foot behind the cab with your gas axe.

I think I would also find some new cab/frame insulators and install them on the center section of the International before I started mating up the center section to the frame clips. I also might box the center section of the International frame for strength, moving the boxing sections into the middle of the frame to leave a "ledge" on the inside of the frame rail for running electrical wiring, brake and fuel lines. This assumes that the International frame is a "C" section frame at that point under the cab. If it's a full box design to begin with, then disregard the boxing information.

Oh, and one last point if doing the 3-part swap, when you still have the donor truck all together, measure from a point on the upper control arm back to the firewall. You don't want to get the front clip all welded in and then discover that you have engine/firewall interference with the International firewall. Also, pay attention to the configuration of the Dakota firewall and take into consideration how the International firewall compares. Even if you have to screw up the "eyeball" a little, it will be better to move the clip a little forward from where the ideal is in order to avoid having to do firewall surgery. Also, pay attention to the clearance between the top of the transmission and the transmission tunnel on the International cab. You may have to adjust the ride height of the cab a little to make sure you don't have to do any surgery on the cab floor for transmission/bell housing clearance.

[edit] Sourcing a doner

If I were looking for a donor like this, I might try finding a truck with a fragged motor and/or transmission to make the purchase price more attractive. The one thing that would be MANDATORY in my opinion, would be a clear Carfax. You don't want to start with a frame that's been tweaked in an accident. I might even take a tape with me to go look at it before the purchase, crawl under and measure on an "X" between points underneath to insure that the frame is square.

At any rate, when all done, it will be a simple task to order replacement chassis/steering/brake parts. Just call up your favorite auto parts place and tell you want a whatchamacallit for a 19XX Dakota. No hassle. All cool.

If you can find a V8 donor, you will also have the advantage of Chrysler Corporation having installed the correct front and rear suspension to take the weight and power and a beefy V8 rear differential as well. How good does it get? Also with a V8 donor, you'll get the power steering pump and all the brackets to work on your 360 "A" motor. Graft the Dakota pedals and power brake booster to the International firewall. You might even want to use some or all of the interior parts from the Dakota. Seats, dash, whatever. I would definitely use the Dakota steering column. It will bolt right up to the steering rack and all is good, as long as the length will work out in the International cab.

You will also have the V8 cooling system in place and positioned properly for your 360 motor. It will be a minor hassle to mount the hood latch and front fender mounts onto the Dakota core support, but you'll figure it out. Same with the bed mounting. You'll figure it out.

[edit] Header/crossmember fitment

There are headers available for the '91-'96 Dakota V8. Hooker makes 'em, part #5803, 1 5/8" primaries, long-tube. These are not shorties. Problem might be, this is a frame swap and there's no way of knowing how the headers will work with the International firewall and center frame portion, so here's how I might go about it to make sure they would work with the 360 in the International:

I'd weld a piece of 2" X 2" square tubing on the bottom of the Dakota clip cross member and extend it toward the rear of the clip. You can cut it off with your gas axe and grind it smooth later when the swap is complete. I'd build a transmission tail shaft mount on it and install a caster wheel on the bottom of the tubing under the transmission mount, so that the whole clip rolls on the front wheels/tires of the Dakota clip and the caster wheel at the rear of the 2 x 2 (building, in effect a 3-point roller). You'd want to install the caster wheel so that the fore/aft tilt of the clip was the same as factory so that the front suspension geometry (caster) would be unaffected and install the transmission mount so that the motor/transmission has a 3 degree tilt to the rear.

I'd mount the motor and trans I was going to eventually use in the swap into the clip and install the headers on the motor. This way, you could roll the entire clip/motor/transmission into place for connecting to the International frame mid-section and be assured that the engine/firewall, transmission/tunnel and header/frame/body clearance would be good to go and that the motor/trans would have the correct 3 degree back tilt to them. This assumes, of course, that your workspace floor is level. Hopefully, you'll be able to position the centerline of the front wheels/tires somewhere close to the point you determined when "eyeballing" the front wheel/tire position on the International that looked best.

[edit] Springs

If, after the truck is completed, you find that the weight is different enough between what the Dakota weighed and the International weighs and the control arm angle or differential tube to frame is a little off either way, you can order different springs to bring everything into spec by using these guys as a source. If they don't have what you need in stock, they can make it quickly. Just tell 'em what you need to do. Give 'em the original front and rear weights from the donor and the front and rear weights now and tell 'em how much lower/higher you want to go to get back to original on the control arm angles on the front and/or housing to frame measurement in the rear. See Eaton springs for more info.

This operation is not for the faint of heart, but will be a rewarding result for anyone who wants a '49 International that rides, handles, accelerates and brakes as good or better than an OEM late model truck and looks good doing it.

[edit] Another swap example

We had another young man on the forum who was using a '96 Dakota frame under a '40 Dodge business coupe. He was thinking putting the body on the complete Dakota chassis and I suggested that it would end up looking clunky. I explained how to do front and rear Dakota clip swaps and have detailed my answer to him here.....

With the Dakota chassis sitting on a level pad and complete with wheels and tires, remove the front and rear springs so that you can position the front control arms and the rear differential in the relationship that they will have when under load. This may mean finding a complete, running Dakota and taking some readings off the components with an angle finder and a tape. Make up whatever brackets you need to, using scrap steel and allthread to hold the components together at ride height. I CANNOT OVEREMPHASIZE THE IMPORTANCE OF GETTING THIS PART OF THE SWAP RIGHT. PAY ATTENTION.

With the Dodge on a level, flat pad, put jackstands under the frame just behind the firewall and just ahead of the spring arch in the rear just so that the tires are barely off the ground. Take measurements from the firewall to the location of the hood latch on the core support. Remove the hood and fenders. Leaving about 8-10 inches of frame stub in front of the firewall, torch off the front frame clip. Go to the rear and torch off the rear frame clip, leaving enough stub so that you can weld the Dakota rear clip onto it.

Now, drop the body down to exactly where you want it for ride height and level it side to side. If you want a little California rake to it, then position the body for a little rake. If you want the body to be level, then position it level, with whatever ground clearance you want (You do have a 4x4 piece of lumber don't you?). If you want the back lower than the front like a liquored-up Kentucky hillbilly, then position the body that way. What we're doing here is getting the exact ride height and body attitude we want without the use of Fosdick dropped spindles or cut spring coils or any other amateurish monkey business. It'll be all stock with the Dakota ride quality and Dakota steering geometry and Dakota brakes. Cool, huh?

Now, with the Dakota chassis secured at stock Dakota ride height, just like in a real, running example of the truck, mount the motor and transmission into the chassis on the stock mounts (you'll want to use new insulators while you're at it). At the engine crossmember, fabricate a caster wheel (pirate one off a derelict shopping cart or whatever) and attach it under the crossmember, having the caster wheel touch the ground and located slightly to the rear of the Dakota wheels and tires, so that you have a short tricycle. Cut the Dakota front frame clip off the chassis right behind the transmission crossmember. You want to keep the forward/rearward tilt of the front clip in the same position as it was on the Dakota chassis at ride height. If you allow the clip to tilt forward or backward from the factory-designed attitude, trust me, nothing will work properly. Been there, done that. PAY ATTENTION. That's why I'd use the third wheel and make a tricycle out of it, to keep everything like it's supposed to be for stock attitude and angles.

As you move the Dakota front clip into position in the front of the Dodge, you may have to cut the transmission crossmember off and some more of the frame ahead of the crossmember, depending on what's in the way of letting you push the clip back far enough to get the motor up against the firewall. If you have to do this and the transmission wants to dangle, put the trans pan on a creeper and chock it back up to the proper height with wood blocks so you can still roll the Dakota front clip around. Make certain you put a level on the Dakota clip to insure it's not lower on one side than the other. If it's out a little, you can add or let a little air out of one tire to level it up. You will have to trim each of the two Dodge frame stubs and each of the two Dakota clip stubs as you move the Dakota clip into position. Just keep trimming and moving and measuring for equal wheelbase side to side until you get it there and you see how you are going to join the stubs together. You can be measuring from holes in the frame on the Dodge and the Dakota that you know are the same distance left to right in order to keep the wheelbase equal. Once you feel like you're close, have a couple of buddies hold one of the front fenders in position so you can eyeball the car from the side and check the position of the tire in the wheelwell. This is where you want to PAY ATTENTION, as this relationship will make or break the swap. Once you have the clip in place, make up your 2" x 4" "Z" components to join the stubs together. Tack them in place for now, you can finish welding them later and add flat "fish plate" reinforcements to the sides of the joints. You may have to make minor changes, so don't finish weld until you know that everything is absolute right. Having the motor/trans installed in the Dakota clip will allow you to bolt the headers up and cut the Dodge sheetmetal and other things that get in the way of the headers. Make the headers fit with no interference, then use scrap metal to fill in the holes or divots that you had to make to clear the headers. Never let anything get in the way of installing a good set of tuned, long-tube headers.

Do the same with the rear, making a tricycle with a caster wheel so that you can just wheel the clip up into place, same way you did in front.

There it is. You have a roller. Mount the core support from the Dakota so you can use the Dakota cooling system, ALL OF IT. Use what has already been engineered at the factory to work, not some Fosdick cobbled up mess from a catalog.

My explanation may sound simple to you, but believe me, this is the pinnacle of automotive fabrication and will take every ounce of your skill and determination to accomplish properly. But I'll tell you, when you get the old girl running and she handles, steers and stops properly, you'll be grinnin' from ear to ear.

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