Retrofitting 1973-80 AMD Inner Fenders On 1981-87 Square Body Chevy

Gaining some clearance With Harrison’s Rod & Custom

By Jason Chandler   –   Photography Supplied by Harrison’s Rod & Custom

One of the biggest concerns for truck owners, especially when you love the lowered truck look, is clearance. I remember back in the day grabbing the reciprocating saw and removing anything necessary to get as low as possible. As I have refined my taste and my concern for the longevity of my projects, I look for an elevated approach to modification. I’ve been looking for a way to do just that and bring you guys along in the process. Enter Bryan Harrison of Harrison’s Rod & Custom.

01 the 5-inch drop on the front has some clearance issues when this ‘89 Chevy Suburban
As you can tell, the 5-inch drop on the front has some clearance issues when this 1989 Chevy Suburban hits a bump in the road.
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Harrison is known for hot rods with a true foundation in street rodding. His unique style continues throughout the Square body platform and is seen in each build they produce. With the builds Harrison’s Rod and Custom produces, driveability is of upmost importance. The Harrison style is true to hot rodding; you can always tell one of his builds apart from the rest. Staggered wheels and meaty sidewalls are a staple and you got to have clearance for that to work. With the popularity of the 1973-87 GM trucks, nowadays there are always a couple of Square body trucks in his shop. Harrison and I got to talking about this topic and he had the perfect scenario.

02 inner fenders arrived from Auto Metal Direct for ’73-80 GM trucks, Blazers, Jimmys, and Suburban
New inner fenders arrived from Auto Metal Direct (AMD). These work on all 1973-80 GM trucks, Blazers, Jimmys, and Suburbans.

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Harrison has always wanted to install the early 1973-80 Square body inner fenders in the 1981-87 Square body platform and see what he could gain by doing so. The 1973-80 inner fenders have a larger housing and should be able to bolt in without too much fabrication. So, when his customer approached him, he knew we had to document it for Classic Truck Performance.

03 The factory bottle jack is missing like most of these old trucks, but we will need to address the vapor canister mount
Bryan Harrison starts with the driver side inner fender. As you can tell, there isn’t a whole lot to remove here. The factory bottle jack is missing like most of these old trucks, but we will need to address the vapor canister mount. More on that later.

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Daniel Chandler, owner of an 1989 Chevy Suburban (the Suburban carried the “Square” styling through 1991 before getting the OBS upgrade), sourced Harrison’s last summer for a static drop on his Square body Suburban. Sitting on a 5/7 drop, it needed just a little inner fender room but at the time he wasn’t quite ready for a full-on tub. Daniel wanted to stay with a GM look underhood. He recently reached out to Harrison after noticing some rubbing on the factory inner fenders and was ready to get them addressed. With the owner open to the idea of the conversion, Harrison reached out to Auto Metal Direct for the inner fenders and showed us just how easy it is to install with basic tools around the shop.

04 the original inner out and next to the ’73-80 AMD parts, you can see just how much clearance you’re going to gain
With the original inner out and next to the 1973-80 AMD parts, you can see just how much clearance you’re going to gain over the factory ’81-87 inner fender.
05 we need to trim the new inner fender to contour properly with the Suburban’s fender
First mod, we need to trim the new inner fender to contour properly with the Suburban’s fender. You can use tin snips or your cut-off wheel for this.
06 With the trimming done, you can see that the factory hole lines up and you can start bolting it in
With the trimming done, you can see that the factory hole lines up and you can start bolting it in.
07 The reinforcement brace will need to be opened to line up the boltholes
The reinforcement brace will need to be opened to line up the boltholes. A stubby step bit works great for this. The holes aren’t off very far.
08 you don’t want to go too far and damage the factory threads that you will be using
The same procedure is used for the truck’s inner brace as well. Patience is key; you don’t want to go too far and damage the factory threads that you will be using.
09 The holes at the front that connect to the core support need to be adjusted as well
The holes at the front that connect to the core support need to be adjusted as well. Only slight adjustments are necessary, the factory bolt and washer will cover up these spots.
10 Harrison uses a small pick to mark the panel to drill for the three core support bolts
Harrison uses a small pick to mark the panel to drill for the three core support bolts.
11 Harrison uses a small pick to mark the panel to drill for the three core support bolts
As you can see, the new early square body inner fenders from AMD give you that extra tire clearance and maintain an original look.

12 Here is how the new AMD inner fender well looks like on the Suburban

13 The same process is carried over to the driver side
The same process is carried over to the driver side; all the original wheel arch bolts are reused as well.
14 Harrison applies a light coat of sealer to finish off the installation underneath
Harrison applies a light coat of sealer to finish off the installation underneath.
15 The other part of this conversion deals with modifying the battery tray and overflow canister
The other part of this conversion deals with modifying the battery tray and overflow canister.
16 The battery tray top ears are cut to allow for clearance with the higher sitting position of the new inner fenders
The battery tray top ears are cut to allow for clearance with the higher sitting position of the new inner fenders.
17 Harrison drills a second hole to achieve better stability once the battery tray is in place
Harrison drills a second hole to achieve better stability once the battery tray is in place.
18 The center tab is drilled for mounting on the inner fender
The center tab is drilled for mounting on the inner fender. This serves as a mockup to drill the inner fender for the 3/8-16 x 3/4-inch bolt.
19 Harrison uses factory-style nuts and bolts to attach the battery tray to the inner fender and the main fender inner structure
With the battery tray modifications completed, the inner fender is marked to be drilled for mounting. Harrison uses factory-style nuts and bolts to attach the battery tray to the inner fender and the main fender inner structure.
20 With the battery tray in place you can see it all appears as if it came from GM just like this
With the battery tray in place you can see it all appears as if it came from GM just like this.
21 This ‘89 Chevy Suburban came with a fender-mounted overflow tank
This 1989 Chevy Suburban came with a fender-mounted overflow tank. Harrison remounts that by simply marking the holes, drilling the inner fender, and using the factory bolt and U-nut to remount the reservoir.
22 Moving to the driver side, the vapor canister needs some slight modifications as well
Moving to the driver side, the vapor canister needs some slight modifications as well.
23 The canister bracket is marked to be cut as the early model inner fenders interfere with the lower foot on this bracket
The canister bracket is marked to be cut as the early model inner fenders interfere with the lower foot on this bracket.
24 Using his cut-off wheel, Harrison trims the bracket to remove any interference
Using his cut-off wheel, Harrison trims the bracket to remove any interference. Just enough to retain structural integrity.
25 Drill holes as needed to remount the existing harness just like the original
Drill holes as needed to remount the existing harness just like the original.
26 With the modifications completed, you can see there is so much more room for activities
With the modifications completed, you can see there is so much more room for activities.
27 A quick one-day install and the owner will get so many more miles out of these 225_55-18s without the worry of them rubbing
A quick one-day install and the owner will get so many more miles out of these 225/55-18s without the worry of them rubbing. A trip to the local cruise confirms that this conversion is worth the effort.
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Harrison’s Rod & Custom
(423) 823-2111

Auto Metal Direct (AMD)
(770) 692-6372
autometaldirect.com

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