Frame swaps

*This subject comes up often, so I thought I would post this reply I wrote to a rodder who wanted to improve the ride, braking and handling characteristics of his 1949 International KB2 pickup truck. Many of the points I make 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.  

*I like using OEM stuff whenever I can. 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.

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 "A" motor of your choice, 273, 318, 340 or 360. There will be no dinkin' around with fabricating 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.

I like the Gen I 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. Well, not problems really, but the tires might stick out too far and you'd have to use different wheels with a different backset or fender flares or some other such foolishness that can be avoided by using the narrower track Gen I 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 for the International. If not, use the Dakota frame that has a longer wheelbase than the International and section the frame between the cab and differential, then have the driveshaft shortened or order a custom driveshaft. For getting the wheels/tires just right in the wheelwells 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 jackstands under the frame. I'd roll the front and rear tires forward and backward in the wheelwells 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 plumbbob 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 BODY, 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. Having done this insanity for 50 years, I have determined that you don't want any part of the truck lower than 4.000" from the ground when measured at curb weight(ready to drive and with a 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 handy to scoot around under the truck during the build will insure that you have sufficient ground clearance to miss most road obstacles.

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.... and you have to dink with cheezy 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. This ain't rocket surgery. (yeah, I know that ain't the right way to say it, but I like it better).

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. You'll need this information later when you mate the Dakota clip to the International center section to make certain the clip is the same as stock so that you don't screw up the caster that's engineered into the front suspension. Write it down. With the Dakota front clip cut off at the firewall and sitting loose, disassemble and remove the springs and shocks. Re-assemble without springs using Allthread, washers, nuts and whatever it takes to put the Allthread in where the shocks mounted to hold the whole mess together without the springs 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. 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.

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/bellhousing clearance.

There are headers available for the '91-'96 Dakota V8. Hooker makes 'em, part #5803, 1 5/8" primaries, long-tube. These are REAL tuned headers, 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 crossmember 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 tailshaft 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.  

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 doin' it.