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The classic truck market has long been the bastion of affordability when it comes to the vintage automobile market, but the recent popularity of these domestic trucks has created a vacuum for old, cheap farm trucks. No longer are the days of dragging an old field hauler out of a barn and back onto the street for pennies on the dollar. People have gotten wise to the fun that can be had in a classic truck and, thanks to the support of an ever-growing aftermarket, all the performance parts that were originally designed for the muscle car crowd has leached its way into the classic truck market. That has helped drive up both the popularity and the desirability of these trucks, to the point where they are no longer the affordable alternative they once were.
This applies essentially to the short bed trucks of the era, though these have always been more desirable to the "hot rod" crowd due to their sportier appearance and maneuverability. For years, if one was searching for a truck to make a hot rod street truck out of, the short bed was the truck of choice. The long bed pickups, for all their similarities, just didn't fit the bill when it came to building a souped-up truck, and were often overlooked. Over time, savvy builders realized that it didn't take much more than a Sawzall and a welder to convert these long bed farm trucks into their sportier short wheelbase brethren and it was "game on". These oft-overlooked longbeds could be picked up for a song as compared to their more "desirable" stubby siblings and after cutting one down, a guy could build a truck that was just as capable as a factory shorty on a shoestring budget.
Nowhere is this dichotomy more evident than with the 1967-72 Chevy C10 trucks. Over the last twenty or so years, the market for these trucks has exploded due to their extreme popularity. An affordable, shortbed second generation C10 is like the Great White Buffalo of the classic truck world. Not only are they hard to find, it's extremely rare to find one that's actually affordable. Those of us in the market for a C10 and on a budget don't have much of a choice when it comes to building a '67-72 C10, unless of course we want to settle for a long bed truck. What makes this disjunction even more strange is the fact that many a long bed C10 can still be found being used as it was originally intended, hauling any number of goods and people from point A to point B. While the shortbed trucks are squirreled away and kept under lock and key, the long bed trucks are being rode hard and put away wet, oftentimes parked on the street to boot. Suffice to say, it's become obvious to savvy truckers that the key to building an affordable C10 is to go the long bed route.
But for some of us, our aspirations outweigh our abilities, so simply cutting up a long bed chassis to convert to shortbed specs might be out of our wheelhouse. And that's precisely what motivated the guys at Brothers Trucks to develop their Long bed to Shortbed Conversion Kit for '63-72 Chevy trucks. Using a carefully developed template, they've put together a system that only requires the end user the ability to operate a drill and a sawzall for a simple, yet effective conversion kit. By using a few pre-existing holes, the Brothers template bolts in place and accurately aligns the necessary holes to be drilled and seams to be cut that essentially prevents the user from making a mistake. Careful work allows a special C-channel bracket to mate the subsequent front and rear frame sections back together, to be then welded by a certified welder. This simple kit equips anyone from the entry level beginner to the professional fabricator the tools for a successful conversion. Follow along as Clampdown Competition installs a Brothers Long bed to Shortbed Conversion Kit on a 1972 C10 and you'll see what we mean!
With the bed removed from our 1972 Chevrolet C10, we're ready to pull the truck into the shop to begin the preparation for converting its wheelbase from 127 inches down to 115.
Since this was a running/driving truck, there were quite a few things that needed to be removed before the shortening could commence. The dual exhaust was cut just in front of the hangers and set aside to be shortened later, followed by the two-piece driveshaft, which will be replaced entirely by a one-piece unit. All three fuel lines (inlet, return, and vent) were also removed along with the rear brake line and intermediate parking brake cable. The rear wiring extension was also disconnected and stowed towards the front of the vehicle. For safety's sake, we also removed the fuel tank from the cab and set it outside in a safe space.
This riveted exhaust hanger also needs to be removed before we can begin. Some trucks have these hangers on both sides of the chassis, your results may vary.
The Brothers Trucks '63-72 Longbed to Shortbed Conversion kit (p/n LTSC372) consists of two templates, two "C" channel plates, hardware kit, shortbed intermediate parking brake cable, and shortbed hydraulic brake lines.
A Cab Mount Kit (p/n CMS6772) is a recommended add-on since we'll have access to them during the conversion.
Speaking of cab mounts, removing the rear cab mount bolts, washers, and sleeves is the first step before we really get started. We did the aforementioned work on a 4-post lift as it made access to the underside of the cab much easier. The rest of the conversion will be made on the floor, with the truck supported by jackstands.
To support the chassis throughout the conversion, a pair of jackstands are placed under the front cab mount to support the front half of the frame, while another pair are placed directly under the front bed mount. These are only adjusted high enough to support the frame, leaving all four wheels firmly planted on the ground; shims may be needed to achieve this without actually lifting the vehicle. The cab is then carefully raised until adequate access is achieved between the floor and the frame, being careful to not "crash" the cab into the front sheetmetal or damage any other components. A pair of jackstands are then placed under the outrigger support braces under each cab corner.
With the cab in the air, the cab mount bushings can be removed.
Some trucks feature a "spoon-shaped" support formed on the bottom of the framerail that will foul the template. Brothers has laser cut the templates, making the removal of this section effortless, allowing the template to then slide into place.
To locate the templates on each side of the frame, two factory holes are used. On our 1972 chassis, we found that only one hole on either side existed (note installed fastener).
Thankfully, these holes are marked by a number "1" on the template, so it's an easy matter to line up the matching hole, then drill the missing hole through the template and the framerail. Note the location of the template, approximately 3/8-inch from the rear cab mount, for reference.
With the templates attached to the frame, there are five 1/8-inch holes that need to be drilled on the section marked "2 Drill", four on the face and one on the bottom.
A Sawzall then makes quick work to cut through the frame and template using the laser-cut guide lines as reference.
There's no turning back at this point! With both sides of the frame cut, the rear half of the chassis is then rolled out from under the cab so the remaining modifications can be carried out.
With the template still attached to the rear portion of the frame, the holes on the "4 Drill" labeled section are drilled using the same 1/8-inch drill bit. There are two holes on the face of the frame, as well as one on the top, and one on the bottom.
With these four holes drilled, the Sawzall is used once again to cut the frame at the second laser cut line on the template.
That section of framerail represents the twelve inches that needs to be removed to change the long bed wheelbase to shortbed specs. The template is removed from the section of framerail and set aside, to be used again a bit later in the process.
Next, those 1/8-inch holes on the front and rear frame sections need to be drilled out to 3/8-inch. There are eighteen holes total, nine on each side, that need to be drilled straight and true before we continue.
The rear cab mounts now need to be removed, along with the front bed mount. An air chisel knocks the head off each rivet, before they're punched out. The front bed mount is discarded, while the cab mount will be reused shortly.
We're going to use the template once again to relocate the cab mounts, but before we do so, the bottom of the template needs to be trimmed along the laser-cut lines to allow the template to sit flush on the framerail without fouling the rivets for the crossmember.
Once trimmed, the template can be placed up against the framerail and fastened into place using the marked holes on the template that correspond to the year of the truck and the existing rear holes for the cab mount.
A pair of 1/8-inch holes are then drilled, once again using the labeled pilot holes in the template that correspond with the truck's year ("72" for '67-72 and "66" for '63-66). Once drilled, the template can then be removed and set aside, but not discarded! The 1/8-inch holes are then drilled out to 3/8-inch.
Using the supplied hardware, the old cab mount is installed using the two new 3/8-inch holes drilled in the previous step. Since there can be slight play in the cab mount, a digital angle finder is used to install the cab mount at the same angle as the top of the framerail, before the fasteners are tightened.
Another pair of 3/8-inch holes are drilled for the two rear cab mount fasteners, using the cab mount as a template.
Like the 12-inches taken out of the frame under the cab, the cab mounts should have moved towards the rear of the truck that same amount when it's all said and done.
The final use of the templates will be to mark the rear of the frame for the removal of the additional eight inches that makes up the long bed's total length. The bumper brackets and bed mounting holes will also be transcribed to their new location using the template. First, with the template flipped upside down and aligned with the rear edge of the frame, a scribe mark is made at the rear of the notch. The oval hole in the template is also traced onto the framerail and will act as the new bed mount location.
A square is then used to scribe the side of the framerail aligned with the top scribe line.
A quick check reveals we're spot on with our work, with our cut line scribed at exactly eight inches from the rear of the frame.
Once again, a nice, straight line is cut through the frame using a sawzall and a sharp blade.
The template is once again used to transfer the bumper bracket holes to the framerail.
We've found that many trucks already have these holes for some curious reason. Note the oval bed mount hole on the top of the framerail that we marked a few steps back. This was created by drilling two 1/2-inch holes in close relation, followed by careful file work.
With the modifications to the rear of the frame complete, the C-channel support bracket is fastened in place and we're ready to slide the frame section back under the cab of the truck and make the chassis complete again.
If all the fasteners easily slide into place, the job has been done correctly. At this point, the truck can be taken to a qualified welder or can be moved to a more convenient location in the shop for final welding. Note the chamfer that was made to the edge of both sides of the chassis before the C-channel was installed. This will serve to allow a stronger, better-penetrating weld joint.
We opted to weld the frame with the truck back on the four-post lift so that we had comfortable access to the chassis while welding and subsequent grinding. Here, the vertical seam has been welded, an inch or so at a time, to allow for adequate cooling between passes. While the frame is bolted together and shouldn't move, there's no reason to introduce unnecessary heat that could warp, tweak, or otherwise affect the final product. Note the three holes that have been plug welded. This effectively fuses the frame rail to the inner C-channel while also filling the unsightly holes left behind on the sides of the frame. We'll use the same process on all the 3/8-inch holes, removing the fasteners and welding up the holes, one-by-one, until they're all filled. The perimeter of the C-channel will be welded up on the inside of each frame rail as well, providing a super-strong joint. Here, that weld is evident by the two vertical dark stripes on the outside of the four outer-most fasteners. This is a good sign that we've achieved adequate penetration in our welds.
A smooth frame rail was the desired outcome, so after all the welding was said and done, a few minutes with a 4-inch grinder was used to knock down all the welds nice and smooth.
A quick coat of semi-gloss black will prevent any rust from creeping into our hard work until the owner of the truck decides to detail the chassis. At this point, the short bed conversion is complete and all that's left is to trim each side of the exhaust, reinstall the fuel lines, install the new brake hard lines and e-brake cable, and measure for a new one-piece driveshaft.
Out under the sun, our long wheelbase conversion is ready to receive its shortbed. A couple quick measurements show the Brothers Trucks conversion kit got our truck within a 1/32-inch, a lot better than GM's OE tolerance commonly found on these old trucks!
