What Happens to Your Classic Car's Interior and Exterior Trim During an EV Conversion: A Guide to What Changes and What Stays

A gasoline to electric conversion does not require sacrificing your classic car's appearance, and the result is road-legal in Hong Kong when performed by a certified specialist. In a properly executed vintage car electric conversion, the exterior bodywork, chrome trim, and period-correct interior materials are preserved or professionally restored as part of the process. The changes are concentrated under the bonnet and beneath the cabin floor, where the combustion drivetrain is replaced by an electric powertrain. The aesthetic soul of the vehicle, its lines, its cabin, its character, stays intact.

TL;DR

• Exterior bodywork, chrome trim, and glass are untouched in a quality electric classic car conversion.

• Interior surfaces such as upholstery, wood trim, and gauges are typically preserved, restored, or upgraded during classic car modernization.

• The drivetrain tunnel and firewall may require minor modifications, but these are concealed and non-destructive to the vehicle's visible character.

• Battery placement is engineered around the car's existing structure, not the other way around.

• A responsible conversion should leave the car looking more refined than when it arrived, not less.

About the Author:

This article is written by the engineering and restoration team at Refined Motor Co., Hong Kong's only road-legal EV conversion specialist, with hands-on experience converting classic and vintage vehicles for private clients and automotive business partners.

What Does an EV Conversion Actually Touch on a Classic Car?

The honest answer is: less than most owners fear. The core logic of a vintage car electric conversion is additive, not destructive. The internal combustion engine, fuel system, and exhaust are removed. A purpose-built electric motor, battery pack, and control electronics take their place. Every other system, structural, aesthetic, and mechanical, is retained wherever possible.

Here is a clear breakdown of what is affected versus what is not:

Component	Status After Conversion	Notes
Exterior bodywork and paint	Unchanged	No cutting or modification required
Chrome and exterior trim	Unchanged	May be polished or restored if the project includes a full restoration
Glass, seals, and weatherstripping	Unchanged	Replaced only if already deteriorated
Interior upholstery and door cards	Preserved or restored	Authentic materials used if restoration is included [1]
Dashboard and gauges	Largely preserved, some gauges updated	Fuel gauge replaced with a battery state-of-charge display
Wood and veneer trim	Preserved or refinished	Specialist care required to avoid moisture damage [5]
Engine bay	Fully replaced	Electric motor, controller, and cabling installed
Transmission tunnel	Minor modification possible	Depends on motor and gearbox configuration
Floor and boot area	Modified for battery housing	Battery pack integrated into existing structure
Exhaust and fuel filler	Removed	Blanked off cleanly; charging port replaces filler

What Happens to the Interior During Classic Car Modernization?

The interior is where most owners feel the most anxiety, and where a quality conversion actually delivers a pleasant surprise. Classic car modernization at a professional level treats the cabin as a restoration project running in parallel with the mechanical conversion, not as an afterthought.

Key interior considerations include:

• Upholstery: Seat foam, leather, vinyl, or cloth coverings are assessed for deterioration. Specialist upholstery craftsmanship using authentic materials and hand stitching are applied to maintain the vehicle's original character [6]. Where materials have degraded, modern reproductions that match the original texture and colour are available [1].

• Dashboard: The original dashboard shell is retained. The fuel gauge is typically replaced or repurposed to show battery state of charge. Other original gauges, temperature, oil pressure, and speed, may be retained or recalibrated. Cracks, fading, or warping in dashboard materials are repaired using appropriate fillers or surface treatments [2].

• Wood and veneer trim: Wooden interior panels require careful handling. Heat, humidity, and sunlight are the primary enemies of classic wood finishes [5]. During a conversion, any woodwork is removed, inspected, and refinished if needed before being refitted.

• Carpeting and headliner: These are often replaced during a full restoration using materials that match the original specification.

• Odour and cleanliness: Years of petrol fumes, oil residue, and organic deterioration are eliminated when the combustion system is removed. A thorough interior detail after conversion addresses ingrained smells and surface contamination [3].

The net result is a cabin that looks and feels authentically original, but performs with none of the mustiness or wear that decades of use leave behind.

Does the Exterior Trim Change at All?

Building on the interior picture, the exterior story is even simpler. A responsible electric classic car conversion requires no modification to exterior bodywork. The bonnet, boot lid, doors, wings, and all chrome or brightwork remain as found, or are improved through detailing and restoration work carried out as part of the project [4].

The one visible exterior change is the charging port. This replaces the fuel filler cap. When done well, the charging port is integrated into an existing recess or a sympathetic location on the body, maintaining the vehicle's silhouette. From five metres away, the car is visually identical to how it left the factory.

What detailing experts recommend for exterior preservation during and after conversion [4]:

• Clay bar treatment to remove contaminants before paint protection is applied

• Wax or ceramic coating application after all mechanical work is complete

• Chrome polishing with non-abrasive compounds to restore original lustre

• Rubber seal conditioning to prevent cracking after reassembly

Where Does the Battery Go, and How Does It Affect the Car's Structure?

Battery placement is the most technically complex decision in a classic car conversion, and it directly determines whether the vehicle's floor, boot, or cabin layout needs to change. A well-engineered conversion works with the car's existing geometry rather than against it.

Common battery placement strategies:

• Boot-mounted packs: Most common approach; keeps the cabin fully intact and uses existing structure

• Under-floor packs: Distributes weight evenly; may require minor floor modifications hidden beneath carpeting

• Engine bay integration: Some battery modules are placed where the fuel tank or ancillary systems once sat

Post-conversion range is typically 200 to 300 km on the WLTP cycle, determined by how much space and weight the vehicle's structure can accommodate for battery capacity. A heavier or larger vehicle generally allows for a bigger pack and therefore greater range.

Regarding motor technology: Refined Motor Co. is currently transitioning to axial flux motors, a form of motor architecture currently found only in supercars and ultra-luxury vehicles. Axial flux motors are significantly lighter and more compact than conventional radial motors, which is a meaningful advantage when packaging components into a vintage bodyshell without compromising interior space.

What Should You Expect From the Full Restoration Element?

Not every conversion includes a full restoration, but for clients who want their vehicle returned in concours condition, the two processes run together naturally. Mechanical access required for the conversion provides an opportunity to address interior and exterior wear that would otherwise require separate dismantly.

A restoration carried out alongside a conversion typically covers:

• Interior fabric and leather replacement using authentic materials [1]

• Gauge refacing and chrome knob polishing [2]

• Wood trim refinishing [5]

• Exterior detailing, paint correction, and protective coating [4]

• Rubber seal and weatherstrip replacement

• Proper long-term storage preparation if the vehicle will not be used immediately after completion [7]

Frequently Asked Questions

Will the conversion affect my classic car's originality or value?

A professionally executed conversion preserves the vehicle's bodywork, trim, and interior. Many converted classics command a premium because they combine heritage aesthetics with modern reliability. The conversion is reversible in principle, and the original character is maintained throughout.

Does the fuel filler cap need to be removed?

Yes. The fuel filler is removed and the recess is repurposed for a charging port, or cleanly blanked off. The visual impact is minimal and is designed to complement the car's existing lines.

Can I keep my original dashboard instruments?

Most original instruments can be retained. The fuel gauge is typically repurposed to display battery charge level. Speedometers, temperature gauges, and decorative instruments are preserved where possible.

What happens to the interior smell after conversion?

Removing the combustion system eliminates the primary source of fuel and oil odour. A post-conversion interior detail removes residual contamination. Many clients report the cabin smells cleaner than it has in decades [3].

Is the conversion road legal in Hong Kong?

Refined Motor Co. is the only provider of road-legal electric vehicle conversions in Hong Kong. All conversions comply with local transport authority standards and use proprietary technology that meets road-legal requirements.

How long does the battery and drivetrain warranty last?

Refined Motor Co. provides a 5-year, unlimited mileage warranty on the electric drivetrain and battery system, covering all conversion components and performance specifications.

Does the conversion change how the car drives?

The driving character of the vehicle is preserved. Electric torque delivery is smooth and immediate, which many drivers find enhances rather than diminishes the classic driving feel. The weight distribution is carefully managed during battery placement to maintain handling balance.

About Refined Motor Co.

Refined Motor Co. is Hong Kong's only road-legal electric vehicle conversion specialist, founded by a team of engineers with a mission to extend the lives of classic and vintage vehicles through electrification rather than scrappage. The company operates bespoke conversion services for private clients and a full turnkey OEM conversion programme for automotive businesses, covering everything from vehicle sourcing and conversion to quality control and aftersales support. Refined Motor Co. holds patents on its modular electric powertrain and battery systems, has received the TVB ESG Award and Top 100 Greater Bay Tech Startup recognition, and is backed by HKSTP and Cyberport incubation programmes. Every conversion carries a 5-year, unlimited mileage warranty on the electric drivetrain and battery system.

Thinking about converting your classic or vintage car to electric, or exploring a B2B partnership for your automotive business?

Learn more and get in touch with the Refined Motor Co. team at www.refinedmotor.com

References

1. Restoring Classic Cars: Finding the Original Look with Modern Materials - Alonso Mercader (alonsomercader.com)

2. Classic Car Interior Restoration Guide | Rod Doors (roddoors.com)

3. Classic Car Interiors - Cleaning, Care & Upkeep Guide (etypeuk.com)

4. What to Know When Detailing for Classic Cars (www.cvautospa.com)

5. Secrets to Maintaining Your Classic Car's Interior Wood Finishes - Bamboli LTD (www.bamboliltd.com)

6. Traditional Upholstery Techniques for Classic Cars (raybuck.com)

7. The Best Way to Store a Classic Car at Home: The 2026 Professional Gui - InTheGarage (inthegarage.com)