Choosing the Right Van for Your Conversion: A Builder's Perspective
We build on Sprinters, ProMasters, and Transits. Here's an honest look at each platform's strengths and trade-offs so you can pick the right van for your build.
The three best vans for conversion are the Mercedes Sprinter, RAM ProMaster, and Ford Transit. Sprinters have the best resale value and diesel longevity (300K+ miles). ProMasters offer the widest interior (~75") and lowest purchase price ($20K-$35K used). Transits have the tallest interior (~81" high roof) and easiest dealer service network. Emery Custom Builds works on all three platforms at our San Diego shop.
The van you choose is the foundation of your entire build. It determines your interior dimensions, your budget, your maintenance costs, and to some degree your resale value down the road. People agonize over this decision, and honestly, all three major platforms make great conversion vans.
We build on all three at our shop in San Diego — Sprinters, ProMasters, and Transits. Here's what we've learned about each one from actually working on them day after day.
Is the Mercedes Sprinter a Good Van for Conversion?
The Sprinter is the most popular van conversion platform for good reason. It has the strongest resale value, the most developed aftermarket parts ecosystem, and a diesel engine that routinely goes 300,000+ miles with proper maintenance.
Strengths
- Resale value: Best in class. A well-built Sprinter conversion holds its value better than any other platform. This matters if you plan to sell it eventually.
- Diesel longevity: The OM642 and OM654 diesels are proven engines. 250K–400K miles is realistic with regular maintenance. Diesel also means better fuel economy for highway driving (18–22 MPG).
- Aftermarket support: More parts, more accessories, more information available for Sprinters than any other van. If you need a specific bracket, adapter, or component, someone makes it for a Sprinter.
- Multiple wheelbase and roof options: 144" and 170" wheelbases, standard and high roof. The 170" high-roof is the most popular for full builds.
Trade-offs
- Purchase price: Most expensive to buy — both new and used. A used high-roof 170 with reasonable mileage typically runs $35K–$55K.
- Maintenance cost: Mercedes parts and dealer labor are expensive. Oil changes run $200+ at the dealer. The DEF (diesel exhaust fluid) system can be finicky on older models.
- Narrower interior: About 5–6 inches narrower than a ProMaster at the widest point. Still workable, but you feel the difference in tight layouts.
- Rear-wheel drive: The standard Sprinter is RWD, which means the driveshaft tunnel runs through the middle of the cargo floor. 4x4 models exist but cost significantly more.
For a detailed comparison, see our Sprinter vs ProMaster and Transit vs Sprinter breakdowns.
Is the RAM ProMaster a Good Van for Conversion?
The ProMaster is the value play in the van conversion world. It has the widest interior of any full-size cargo van, costs less to buy than a Sprinter, and the front-wheel-drive layout gives you a flat cargo floor with no driveshaft tunnel.
Strengths
- Widest interior: About 5–6 inches wider than a Sprinter at shoulder height. This makes a noticeable difference in layouts — especially for cross-wise beds, where every inch of width matters.
- Flat cargo floor: Front-wheel drive means no driveshaft tunnel running through the floor. The entire cargo floor is flat, which simplifies floor insulation and subfloor installation.
- Lower purchase price: Cheapest of the three platforms to buy, both new and used. A good used ProMaster typically runs $20K–$35K.
- Easier maintenance: The Pentastar V6 gas engine is well-understood and cheaper to service than the Sprinter's diesel. Any Dodge/Ram dealer can work on it.
Trade-offs
- Lower resale value: ProMaster conversions don't hold their value as well as Sprinters. This is a market reality, not a quality issue.
- Gas engine: The 3.6L Pentastar is a solid engine but gets worse fuel economy than the Sprinter's diesel (14–18 MPG) and has a shorter expected lifespan (200K–250K miles vs 300K+ for diesel).
- FWD handling: Front-wheel drive is great for traction in rain and light snow, but the turning radius is worse than the Sprinter's, and loaded ProMasters can feel front-heavy in crosswinds.
- Body style: Let's be honest — the ProMaster looks like a delivery van more than the Sprinter does. If aesthetics matter to you, this is worth considering.
Is the Ford Transit a Good Van for Conversion?
The Transit is the middle ground between the Sprinter and ProMaster. It offers the tallest available interior height, a reliable gas engine that any Ford dealer can service, and a strong balance of capability and value.
Strengths
- Tallest interior: The high-roof Transit has more headroom than any other van. If you're tall (6'2"+), this is the platform where you'll stand fully upright without ducking.
- Easiest to service: Ford dealers are everywhere. The 3.5L EcoBoost V6 is a mass-market engine with affordable parts and knowledgeable mechanics in every town. No hunting for a diesel specialist.
- AWD available: Ford offers factory AWD on the Transit, which is a simpler and cheaper solution than aftermarket 4x4 conversions on the Sprinter.
- Multiple configurations: Three roof heights, three wheelbases. More configuration options than the other platforms.
Trade-offs
- Narrower than ProMaster: The Transit is similar in width to the Sprinter — narrower than the ProMaster. This limits cross-wise bed options in shorter models.
- Gas fuel economy: The EcoBoost engine is powerful but thirsty under load (14–18 MPG). The twin-turbo setup also adds maintenance complexity compared to a naturally aspirated engine.
- Less aftermarket support: Growing but still behind the Sprinter's ecosystem. More aftermarket parts and guides appear every year as Transit builds become more popular.
- RWD driveshaft tunnel: Like the Sprinter, RWD models have a driveshaft tunnel in the floor. AWD models have it too but less pronounced.
Should I Buy a New or Used Van for Conversion?
Most of the vans we build on are used — typically 2–5 years old with 40K–100K miles. Here's our reasoning:
Used vans save $15K–$30K off the purchase price. A Sprinter diesel with 80K miles still has 200K+ miles of engine life ahead of it. ProMasters and Transits with 60K miles have plenty of life left too. The depreciation curve on cargo vans is steep in the first two years, then levels out — buying a 2–3 year old van gets you past the steepest drop.
New vans come with a factory warranty (which doesn't cover the conversion, but does cover the drivetrain), zero mystery history, and you can spec exactly the options you want. If budget isn't the primary concern and you want the peace of mind, new makes sense.
What to inspect on a used van:
- Rust: Check wheel wells, rocker panels, undercarriage, and under the cargo floor mat. Surface rust is manageable; structural rust is a deal-breaker.
- Water leaks: Look for staining on the headliner and upper walls. Cargo van roofs can leak around seams, especially on older models.
- Engine and transmission: Get a pre-purchase inspection from a qualified mechanic. For Sprinters, use a diesel specialist. A $150–$200 inspection can save you from a $5,000+ repair bill.
- Service records: Regular oil changes and scheduled maintenance are good signs. Gaps in service history are yellow flags.
- Sprinter-specific: Ask about DEF system issues, turbo condition, and injector service history. These are the common expensive items on Sprinters.
How Do Sprinter, ProMaster, and Transit Compare?
| Sprinter | ProMaster | Transit | |
|---|---|---|---|
| Engine | Diesel (standard) | Gas V6 | Gas V6 (EcoBoost) |
| Drive | RWD (4x4 available) | FWD | RWD (AWD available) |
| Interior Width | ~70" | ~75" | ~70" |
| Interior Height (high roof) | ~76" | ~76" | ~81" |
| Used Price Range | $25K–$60K | $20K–$40K | $20K–$40K |
| Fuel Economy | 18–22 MPG | 14–18 MPG | 14–18 MPG |
| Resale Value | Best | Lower | Middle |
| Flat Cargo Floor | No (RWD tunnel) | Yes (FWD) | No (RWD tunnel) |
Dimensions are approximate and vary by model year and configuration. Measure your specific van.
Which Van Platform Do We Recommend?
All three platforms make great conversion vans. We build on all of them and can produce an equally great build on any platform. The "best" van is the one that fits your budget, your intended use, and your preferences.
If resale value and long-term engine life are your top priorities, the Sprinter wins. If you want the most interior space for the money, the ProMaster wins. If you want the tallest interior and the easiest maintenance access, the Transit wins.
Don't overthink it. Pick the one that checks the most boxes for your situation, get a good pre-purchase inspection if buying used, and focus your energy on the build itself. That's where the real magic happens. For more detail on what goes into the build, see our best van for van life comparison.
What Are the Most Common Van Selection Questions?
What is the best van for a conversion?
It depends on your priorities. Sprinter for resale value and diesel longevity. ProMaster for widest interior and lowest purchase price. Transit for tallest interior and easiest maintenance. All three make excellent conversion vans.
Should I buy new or used?
Used saves $15K–$30K and still gives you a van with plenty of life left. A 2–3 year old van with 40K–80K miles hits the value sweet spot. New gives you warranty and zero history. Either works — just get a pre-purchase inspection on used vans.
Does the van platform affect build cost?
Build cost is driven by scope and finish level, not the platform. A similar build costs roughly the same across all three vans. The vehicle purchase price is where platforms differ most. Professional builds range from $30K–$50K (basic) to $80K–$120K+ (premium).
Related: All How-To Guides • Systems & Guides
Need Help Deciding?
We build on Sprinters, ProMasters, and Transits. Tell us what you're looking for and we'll help you figure out which platform fits your build.
Tell Us About Your Build