We purchased this project mostly mechanically intact. The drivetrain was in very good shape, and the entire exhaust including the ceramic coated headers was brand new. The previous owner had professionally installed a true dual-pipe arrangement, which meant switching out the crossmember for a beefy aftermarket piece so the exhaust could pass through. The drivetrain is still factory-issue, with the original 350 cubic inch engine backed by a TH350 transmission. The rear gear ratio appears to be 2.73, so while not great for acceleration it should be fantastic for fuel mileage.
The suspension front end was almost entirely rebuilt, and the rear suspension was in good shape. The factory air shocks are replaced with standard hydraulic shocks. We're not sure how we feel about this modification, and might change it back. This car was being used as a daily driver when we scooped it up, as the owner had to sell it, so mechanically it appears to be well maintained and in great shape. The factory 4 barrel Quadrajet carburetor looks rebuilt and the car starts right away every time.
Generally there is a ton of cosmetic work that needs done. There is a large dent in the roof that we will be pulling out. The factory color of this vehicle appears to have been gold, repainted in a forest green metallic by a previous owner. There are some dents and issues with the body, and the interior needs a lot of work.
The vehicle has a factory air conditioning system, which appears to have been converted to newer refridgerant and is currently inoperable, so we will be rebuilding the a/c system at some point.
The wheels are not factory correct, being off of a Camaro from the same era. They are very close to the standard wheels though and will work for the look we are going for. Although the missing trim pieces were included in the sale, many are not in great shape and look better than they actually are. We are considering a chrome trim-delete modification to save cost on replacement chrome.
In general, the impresson on arrival is that it drives and handles beautifully but is very cosmetically ragged.
The first order of business was to decipher just how original our El Camino was. There was no surviving label with RPO codes, and we could not locate any of the build sheets during tear-down. We had to back into deciphering everything by a little automotive archeology. Figuring out which parts are original factory parts, and which have been replaced, among other methods such as researching available options and pulling as much information off the car as possible. Some option codes require others, and are linked together, making these easy to assign.
The VIN tells us very little, other than this is a 1978 Chevrolet El Camino 2 door pickup truck with a 350 engine manufactured in Fremont, CA. It's a good starting point though.
The engine casting numbers are appropriate to this time period, so it is likely that the engine is original. We can extrapolate some information based off of the trim level. Some things are uncertain, such as tilt steering, which is easy to add and duplicate a factory install. The codes below are our best extrapolation based off the existing information. It is possible to buy a reproduction build sheet from GM, but we opted not to. This vehicle will be more of a 'restomod' than a direct restoration, as it has already undergone a lot of work over the years by others.
AK1: BELTS, DELUXE: COLOR-KEYED SEAT AND SHOULDER
A42: SIX WAY POWER DRIVERS SEAT
++BX8: MOLDINGS: FRONT FENDER, BODY SIDE AND TAILGATE
C60: AIR CONDITIONING
D68: MIRRORS, SPORT, TWIN REMOTE
FRM: FREEMONT PLANT
J50: POWER BRAKES
**K76: 61 AMP ALTERNATOR
LM1: 350 CUBIC INCH ENGINE
MX1: AUTOMATIC TRANSMISSION
N33: TILT STEERING WHEEL
***N41: POWER STEERING
*T63: HEADLAMP WARNING BUZZER
U05: DUAL HORNS
UX6: RADIO EQUIPMENT: SPEAKERS, DUAL FRONT U14: GAGE PACKAGE WITH TACHOMETER
*U26: ENGINE COMPARTMENT LAMP
*U27: GLOVE BOX LIGHT
*U28: ASH TRAY LIGHT
*U29: COURTESY LAMP
+U35: CLOCK, ELECTRIC
U63 or U69 or U58 or UM1 or UM2: radio, all we know is this vehicle had a factory radio of some type
U76: WINDSHIELD ANTENNA
VE5: BUMPER RUB STRIP FR/RR
**V01: HEAVY DUTY RADIATOR
V30: BUMPER EQUIPMENT: BUMPER AND GUARDS, FRONT AND REAR
VX3: FRONT LICENSE MOUNT
ZJ9: AUXILLARY LIGHTING, UNDERHOOD
56M: ACCENT COLOR: GOLD METALLIC
YF5 or NA6 or NA2: emissions equipment, one of these three must be specified
* included when ZJ9 selected ** included when C60 selected *** required when LM1 selected + included when U14 selected ++ included when D91 selected
Interior seat, headliner, door trim: Camel
Instrument pad and carpet: Camel
Seat: PCC3 knit cloth 50/50, Camel
Axle: either 2.41:1 or 2.73:1
Exterior paint: 69 or 61 Camel (metallic). Unsure of exact match, but it is one of these
Factory tire and wheel size: unknown
Interesting to note is our vehicle has a hood ornament mounted on the front valance. No other pictures or dealer or factory documentation we can find show a hood ornament mounted there. Our best guess is this in not the same valance that came with the vehicle from the factory. Missing are the rear bumper guards and factory stereo. It also has the extra chrome trim package (paint-break moldings) between the bed rail and the mid-body trim line. This makes it a 'Conquista' package, even though the logos on the tailgate and passenger side dash are not there (the tailgate having been repainted and the dash replaced with a black one). This package most likely included a two-tone paint scheme.
In total, this is a nicely equipped El Camino for 1978. It has the largest engine option, although it is automatic. The four speed manual is more desireable in the automotive market. It has some electric power options, but not all, windows and locks particularly missing. It has obviously been repainted green at some point. There are some trim and interior parts missing, and the whole interior will need some work.
The first step was to strip the body and see exactly what we had to work with. We removed all the chrome and trim, bumpers, etc., and evaluated the sheet metal. It was generally very solid with a few spots that needed work, other than the large dent in the roof. We are liking the preview of the look without the chrome trim, and may go that route on the body.
We hammered the roof dent out from the inside with a punch, dolly, and hammer, and then smoothed it with body filler. In the end it required about as much filler as would have been required to smooth a welded patch.
The plastic corner trim piece on the rear driver's side had been mashed in by the bumper. We opted to repair it rather than buy a new one. We removed the piece and baked it in an oven at 200 degrees for about twenty minutes, then pressed it back into shape and maintained it until cool.
The rest of the body got sanded and smoothed, with special attention to areas with surface rust or holes.
This vehicle had been used for work, so the tailgate was scarred and required some elbow grease to get looking decent.
At the end of the day, this thing is still a truck so we opted to not make the inside of the bed and tailgate absolutely silky smooth. The bed had previously been protected by a rubber floor mat so it was in decent shape, but there had been a hinged toneau cover on it at some point in the past that required some patching from hardware and drain holes.
With the body almost fully prepped, we ordered paint and prepared our painting setup. We opted to go with roughly the same metallic green, using a standard GM color code for 'Forest Green'. Using a standard color code will make future body repairs easier, if ever necessary. Here is the car out of the paint stage, getting ready for reassembly:
All of the exterior trim pieces got a good polishing by hand while removed. The difference can be seen below in the same pieces side by side on the red rag. While we did not take it to extremes to make a perfect factory piece, the final result is quite a wonderful change.
Overall, our bodywork efforts resulted in the transformation shown below:
The front grille was not in great shape. The driver's side upper corner was broken off and the rest generally shabby. We opted to repair the existing grille rather than purchase a new one. This isn't intended as a 1,000 point restoration, so 'good enough' was just fine. Our hope is that eventually someone will drive and use this truck, so we don't want to make it a perfect trailor queen anyway.
The chrome-coated plastic was peeling badly. There aren't many good and cheap ways to fix this, unfortunately. We wire-brushed off the loose chrome, and sanded smooth everthing we could. We removed the emblem, which had almost all its factory paint gone. We will be refinishing the emblem also. The next step was to repair the broken corner. We abraided the broken area lightly to provide traction for the fix, then used masking tape to create a rough mold for the epoxy filler.
Once the epoxy was dry, we filed it to the rough shape, then used standard body filler to smooth the surface and malke it conform to the original shape. We used several coats and steps, the photos below show only a rough finish. It took us about three coats and several sanding steps to make it good enough to match the factory fit and finish.
With the unit whole once more, the next step was to prime and sand the entire thing. The factory appearance has the inset portion of the grille black, and the rest chrome, including the inner portions of the openings. We next sprayed the entire unit black, then masked the front of the openings over top the insets, and sprayed chrome from the back and the front(Yes chrome paint is not the best thing in the world, but again we are going for 'good' not 'perfect').
After hand-painting the lettering, we ended up with an acceptable product for very little cost, which was the goal.
With the other front pieces polished as best possible, we reinstalled the front trim and bumper.
Of note here is the front bumper guards, which we opted to leave off. They were too rusted to reinstall and replacements did not seem worth the cost. We filled in the gaps in the bumper impact strip by purchasing a duplicate center piece and carefully splicing it in, which can be seen on close examination. This was cheaper than purchasing an entire new solid impact strip.
The rear bumper had sustained at some point a low velocity inward pressure that had compressed the shock between the bumper and frame on the driver's side. Absorbing some of the impact is the intention of the shock absorber, but once compressed they do not rebound naturally.
Once these fluid-filled impact shocks are compressed, they cannot be easily uncompressed without draining the fluid. We could have opted for complete replacement, but note in the pictures below someone has already placed mis-matched bumper shocks on the rear. A little further modification that is invisible once installed will not hurt it any more.
Once removed from the bumper assembly, the shock can be drained of its fluid and internal pressure by drilling a hole in the casing. We measured the difference between sides and noted we have to pull this one out a little more than an inch.
Using a bearing puller, we uncompressed the shock until it matched the one on the other side. Once the fluid is drained there is little resistance to compression, so we drilled out a hole and installed a through-bolt. Yes it defeats the purpose of the shock, but the one on the passenger side had already been previously welded in place. Modifying this one to match won't hurt anything, and will be invisible once installed. Should this vehicle get in an accident, preserving the bumper will be the least of the drivers worries in any case. But the bolt can still shear and allow the shock to compress, absorbing some of the impact as intended.
The bumper mounted perfectly with our careful measurements, and is now symmetrical with the body.
The rear license plate holder also was in deteriorating shape cosmetically. We sanded the deteriorated areas to get a smooth transition, then masked the areas that were to remain chromed. A quick spray of black paint brought it back to looking good again.
The newly installed rear plate holder:
When we purchased the car the tachometer worked intermittently and the clock not at all. We pulled the cluster to remedy these issues as well as give it a refresh in general. While we had the cluster out we also opted to replace the old worn steering wheel with an affordable used 4-spoke early 90's steering wheel which is more comfortable and not deteriorating like the original.
The factory paint on the needles which flouresces under light was fading badly. We repainted the needles, and checked the gauges by carefully applying the appropriate voltage to the proper terminals. All gauges and clock proved to be functioning.
Below, the before and after shots of the cluster needles. At night it will look much sharper under the gauge lightbulbs.
While we had the cluster out, we replaced all the lightbulbs with LED bulbs for a brighter cluster. It's a cheap solution to dim gauge lighting issues in older cars.
With confirmation that everything in the cluster worked properly, we reinstalled the cluster and paid special attention to making sure the plug was inserted fully. It appears that the last owner did not properly snap in the plug, resulting in some loose or intermittent connections. Below, the new steering wheel and cluster installed, which now works perfectly.
The air conditioning was non-functional when we got the car, although almost all the parts were present. The compressor clutch was broken and the drive belt gone.
We replaced the clutch and belt, and pressurized the system for a test. The compressor makes pressure, although very low. The clutch seems to be having some issues staying engaged as well, with a lot of slipping. Overall the system seems to hold pressure well however.
The compressor was replaced with a remanufactured unit. Virtually no oil remained in the original compressor, this being the A6 type with an integrated oil resevoir, oil inside the compressor resevoir is necessary even if it is also in the refriderant.
During dissasembly, one of the evaporator fittings broke inside the line fitting. We managed to save the (very, very expensive) line but the evaporator core sacrificed itself and was replaced. All the O-ring fittings and the dryer/accumulator were replaced also. We then charged the system.
It functioned great, but there was a leak at the pressure switch. It appears that moving the very old switch from the old compressor to the new unit did not preserve it intact. Researching this switch shows that it is no longer manufactured, and a similar unit that is plug-and-play is not made. We used an appropriate 'conversion' switch which goes on the accumulator rather than the compressor itself. Although it does not function the same way it will still provide a low pressure cut-off in case the system leaks down.
It also appeared that under long duration and the exact right conditions, the evaporator core iced up. There is a thermal switch that is supposed to cutoff the compressor to prevent this. We removed the cutoff switch and tested it, revealing that it did not open at the proper temperature. The best way to test this is a bowl of ice, a thermometer, and a multimeter.
After replacing the thermal switch, the evaporator core no longer ices up as the compressor now shuts off if this happens, and allows it to warm up again enough to function properly. However, we did do our best to reduce the possibility of future icing at all (it shouldn't ever happen under normal operation) by vacuuming the system again and refilling to ensure all air is removed.
We also had some trouble with the belt and clutch on the new compressor. The clutch had been pre-installed, and it turned out to be installed incorrectly. The clutch was slipping, resulting in extra belt wear due to sudden on/off changes, as well as reduced air conditioner functionality.
We removed the clutch and observed (as can be seen in photo below) that the clutch was extremely gouged, blued in spots from overheating, and galled from temporary welding of the clutch halves together during extreme overheating.
This clutch was salvaged by resurfacing, and once reinstalled with a new belt and set to the proper gap functioned perfectly.
We opted to install a trailer hitch to make this vehicle more useful, as it is intended to be a working vehicle not a show queen. Bolt-on class 2 hitches are readily available and relatively cheap, and with a 3,500 lb. hitch limit and a 5,000 lb. factory vehicle limit, will fall within our parameters of light hauling. This hitch bolts to both the bumper mounts and the frame.
We tested the towing capability by hitching up a light 2,000 lb trailer and going for a spin. The vehicle towed beautifully, comfortably, and the field of view with the large amount of cab glass is wonderful. El Caminos are admirably suited to towing when properly equipped.
After initial testing, it seemed our El Camino squatted too much in the rear due to the previous owner replacing the factory air shocks with standard passanger car shocks. We opted to add air bags inside the rear coil springs to improve ride height and handling under load, while still preserving the nice ride of the standard shocks when the bags are aired down unloaded.
At first we installed the airbags as the directions indictated, with the air hoses coming down through the top spring mount pointed upwards. This quickly proved to be a mistake as the flex of the bag tops and the hoses inside the springs did not allow enough spacing even with the poly spacers provided along with the bags that are supposed to prevent this. The bags installed as per the directions worked up until only the first test drive. The hoses quickly kinked and leaked at these points on both sides. We reversed the bags with the hoses coming out the bottom spring mounts, and all worked well.
The driver's side tail light had a melted/broken hole over one of the bulbs. These specific tail lights are slightly different than later years, and are very hard and expensive to locate. We opted to fix ours by carefully cutting a replacement piece from a red reflector, adhering it in place with reinforcement behind, and then blending it with red tinting.
We quickly discovered after starting to drive the vehicle regularly that there was a severe battery drain somewhere. After much tracing and testing, we narrowed this down to the door-open/key-in buzzer, which is located beneath the light switch by the driver's left knee. We removed the unit and discovered it was literally toast. We could not find a replacement for this unit, so for now we will have to do without this option.
We found these resources valuable or interesting for our work:1978 Chevrolet El Camino Sales Brochure
Chassis measurement reference:
Lock/Ignition Cylinder reference:
Fuse block layout: