You can have the perfect paintjob, yet still have a ride that falls short. When you’ve seen as many Chevys as we have through the years you develop a keen eye for detail. You spot the flaws right away: sloppy gaps, uneven panels, and other irregularities.
Our pet peeve with show cars and weekend “under-the-streetlights” cruisers is sloppy body fitment—fenders, hoods, doors, and decklids that do not fit properly. Gaps outrageously wide and sloppy, panels not flush, doors that do not shut properly, a decklid you have to slam close, and a host of other issues make an otherwise nice car uncomfortable to the eye.
Pro Touring also needs to mean pro fit. It is time to think more like a good old-fashioned hot rodder and treat your Chevy to the process known as mock-up, or pre-assembly. A mock-up session is all about taking your Chevy’s body panels and doing a fitment check before body prep and paint begin. The goal should be to achieve perfect door, fender, hood, and decklid gaps and overall fitment (adjacent panels aligned and flush) before you do anything else.
Here’s a factory original 1969 Camaro Z/28. These are the gaps you want focus on. Door and fender gaps are the first thing you see when approaching a car. The most important gaps are those on top that you first see opening doors. The door should sit flush with the quarter-panel with a perfect 1/8- to 3/16-inch gap. GM allows for up to a 1/4-inch, which, in our opinion, is too wide.
Getting It Right
The best time to adjust the fenders, hood, doors, and decklid is during paint prep prior to laying on the color. This is the time when you have the freedom to get all of your Chevy’s body panels correctly positioned and gapped without fear of scratching or nicking fresh paint. If you’ve already had the car painted all is not lost. You just have to be very careful when adjusting and locking down the panels. Then, do any touch-up work once the body panels have been properly fitted. The key is to not damage the paint.
Body panel adjustment is best accomplished and easiest when the body is in primer to observe gaps and panel cohesiveness. If you’re still in old paint, the gaps—depending on the color—are more challenging to see. Light gray primer is the best color in which to set gaps and adjust panels because you can see these dimensions clearly.
Head on, the valance-to-fender gaps should be flush as shown here. The hood-to-fender gaps should be uniform from the cowl to the fascia at 1/8- to 3/16-inch. As long as you have a straight body (good bones), factory sheetmetal gaps should be easy to adjust.
Setting gaps and leveling panels isn’t easy for even the most seasoned body guy, and it depends largely on your eyesight and judgment. You must have a good eye for gaps and straightness. If you’re working with a body that has never been wrecked or ever been apart the chances are good the body dimensions are on the money. However, we’ve seen many low-mileage, unmolested originals with sloppy gaps and panels. Remember, all kinds of people assembled these cars back in the day and a good many of these classic Chevys rolled off the line with notable quality issues.
All body panels have a fitment range in which you can make adjustments, hence slotted bolt holes and the use of shims. The factory used shims to get the fenders level with the hood and flush with the doors. Hood hinges are slotted to get it centered between the fenders. Door hinges are fully adjustable at the body and at the door. Decklids are adjustable at the lid and at the body for full adjustability. If you cannot achieve proper adjustment, something is likely wrong with the body itself.
The decklid should sport uniform gaps for 360 degrees if the quarter-panels and tailpanel are true. If ever you have to replace quarter-panels or the tailpanel do so with the decklid installed and properly adjusted beforehand so you have a solid reference point to work from.
In order to get the doors properly aligned and locked in, you must first have solid hinge bushings and pins. Bushings and pins that are worn out will not hold an adjustment. The gap will continue to degrade more and more as hinge bushings and pins wear out of adjustment. The best advice is to rebuild the factory hinges, which can be accomplished in your garage. Pins and bushings are available from many retailers such as Classic Industries. New old stock GM pins and bushings are also out there in the online classifieds.
Once you have established that the door hinge bushings and pins are of solid integrity, examine the door latches and strikers to ensure they mate smoothly. You should be able to gently nudge the door closed and have it catch. If you have to slam the door, an adjustment is required. The decklid should latch and seat with a nudge. Hoods have always needed a touch more force to get past the safety catch and into the latch.
This is called the priority gap because it is the gap we see most when entering and exiting the car. Because we’re working with mass production vehicles, it is virtually impossible to get a perfect gap because stampings can vary, sometimes by a lot. You may need to grind, fill, and/or finesse the edges to get the gap you want.
Another door adjustment issue is door weight. An empty door weighs less than a door loaded with window glass, the regulator mechanism, and the latch assembly. All of these affect how the door hangs. The doors should be hung with all of these components installed in order to get the gaps where they will be with the car fully assembled. Another important issue is to have the car sitting level on all four tires with the suspension at rest. Unit body cars, like the Camaro and Nova, flex when they’re on jack stands or are being supported by a floor jack. You would be amazed at how much flex there is as you drive down the road or when you’re tackling a canyon pass.
Before you handle the task of body panel adjustment, overall body dimensions need to be checked. How true is the body you’re about to assemble? Has it ever been wrecked and if so was the repair up to par dimensionally? Was the body treated to a frame table where it could be pulled back to factory specifications? These dimensions, which are in any Chevrolet service manual, can be checked before you start adjusting panels.
Readers often ask us what is the best way to measure a gap. Our easy answer is to use a standard paint stirring stick, which is a good unit of measurement of around 1/8- to 3/16-inch.
And finally, all body panel adjustments should begin where the door meets the B-pillar and quarter-panel. If you have the door gap at the B-pillar spot on, the rest should fall in line. Hang and adjust the doors first, then, the front fenders and then the hood. The decklid can be gapped anytime since it’s surrounded by fixed panels. CHP
Decklid gaps, like door gaps, should be the thickness of a paint stick: 1/8- to 3/16-inch. You will find stamping irregularities can cause these numbers to vary to where you get a wavy gap at the quarters. The optimal width is a consistent 1/8-inch gap all around.
If you study the gap around this decklid it tends to wander as it nears the tailpanel. The gap is at the correct 1/8-inch at the top near the deck filler panel but considerably wider at the trailing edge near the tailpanel. Adjustments should be made where the gap at the top is wider, with the side gaps at 1/8-inch. This requires a lot of patience.
The gaps here at the cowl and A-pillar are especially tricky to set. Because this is a complex angle, you have to stay with it until all the angles match along with door gaps the rest of the way. GM specs call for it be around 1/16- to 1/8-inch.
Note how the trailing edge door gap is wider at the top than at the bottom. This is not acceptable. The angle of the door must be adjusted to where this gap is 1/8-inch from top to bottom. The door skin must also be flush with the quarter-panel skin and the front fender.
Door adjustment happens where the hinge meets the door and where the hinge meets the A-pillar. You should never have to remove the hinges from the body, and they should remain where the factory installed them to begin with. Then, you can keep door angle adjustment where the hinge meets the door.
A floor jack is used here to raise and lower the door as adjustments are being made. Ideally, you will position the jack mid-door to get it centered then make finite adjustments. Snug the bolts to where you can finesse the door yet maintain position then tighten the bolts.
The doors are the toughest body components to adjust. Note this door is completely assembled and at the proper weight for installation and adjustment. If you install the door empty it’s not going to maintain its adjustment when it is assembled. It will droop as components are installed.
Here’s a cool trick we learned from AR Auto Body in Lancaster, California. Before the car was disassembled, small 1/8-inch pilot holes were drilled through the hinges into the door and A-pillar to lock in the factory adjustment. This awl is being used as a jig pin to get the hinges back to where they were prior to disassembly.
With the awl stuck through the pilot hole, the hinge bolts are tightened, locking in the adjustment. The door should sit perfect.
Note the perfect door gap thanks to the use of pilot holes and the alignment awl. You could also use a drill bit as a jig pin.
The next daunting task is front fender adjustment, which begins at the door leading edge. Because fenders can be long, a lot of adjustment is required, especially on Camaros. There’s also the wheelhouse to contend with, which should be connected and adjusted last.
These two attachment points at the firewall and cowl may or may not require shims to get the adjustment where it needs to be.
Where the door meets the fender can be a huge point of frustration, especially if you’re working with reproduction sheetmetal. Snug the fender bolts to prevent accidental movement, but do not tighten until all the adjustments are complete.
Where the fender meets the header panel on this Camaro there is no gap. The fender and header panel above the grille are bolted together flush.
The decklid gap at the tailpanel should look like this where the decklid and tailpanel are dead on straight from quarter-panel to quarter-panel. This gap should be 1/8- to 3/16-inch.
These fender bolts at the decklid and hinge allow movement in all directions. Lower the lid and check gaps with these bolts snug, yet loose. If the gaps check out, tighten the bolts and check the gaps again. These bolts should be body color, which means adjustment takes place before the body is painted.
These are adjustment shims used to get the fenders aligned. You should never use them on door hinges or at the hood and decklid.
Photography by Jim Smart