M156 vs M177 vs M178 — Specs, Build Cost & 1,500HP Potential | AMG Engine Guide 2026
M156 vs M177 vs M178 — AMG Engine Comparison
2026 Edition — by YPG Motorsport
AMG has built three distinct V8 engine families over the past two decades. Each has different architecture, different tuning potential, and different build costs. This guide compares all three so you can make the right decision for your build.
Quick Comparison
| Spec | M156 | M177 | M178 |
|---|---|---|---|
| Displacement | 6,208 cc (6.2L) | 3,982 cc (4.0L) | 3,982 cc (4.0L) |
| Aspiration | Naturally aspirated | Twin-turbo (hot-V) | Twin-turbo (hot-V) |
| Crankshaft | Cross-plane | Cross-plane | Flat-plane |
| Oil system | Wet sump | Wet sump | Dry sump |
| Factory HP range | 457–518 HP | 469–630 HP | 476–720 HP |
| Tuning ceiling (with build) | 700–800 HP (NA) / 1,500HP+ (forced induction) | 1,500HP+ | 1,500HP+ |
| Key vehicles | C63 W204, E63 W212, SLS AMG, CLK63 Black | C63 W205, E63 W213, GT63, G63, GLC63, GLS63 | AMG GT, GTS, GTR, GT R Pro, GT Black Series |
| YPG crate engine | From $25,999 | From $29,999 | From $35,000 |
M156 — The Naturally Aspirated V8
The M156 is AMG's last naturally aspirated V8 — a 6.2-litre unit that revs to 7,200 RPM and produces up to 518 HP in SLS AMG trim. It's a fundamentally different engine philosophy from the turbocharged M177/M178. No turbo lag, no boost thresholds — just linear, mechanical power delivery all the way to redline.
For owners who want to stay naturally aspirated, the M156 responds well to CNC-ported heads, cam upgrades, and intake work — realistic targets are 600–700 HP NA. For owners chasing serious power, supercharger and turbo kits push the M156 well past 1,000 HP. The block is strong enough to handle it with forged internals.
Best for: Owners who value the naturally aspirated V8 character and want a proven, well-understood platform with massive aftermarket support.
→ M156 Crate Engine Guide · M156 Short Block Guide · M156 Ported Heads Guide
M177 — The Twin-Turbo Workhorse
The M177 is AMG's most widely used current-generation V8. A 4.0-litre twin-turbo with a hot-inside-V turbo layout and cross-plane crankshaft, it powers everything from the C63 W205 to the G63, E63, GT63, GLC63, and GLS63. Wet-sump oiling in all applications.
The M177 is one of the most tunable production V8s ever built. Stage 1 ECU tuning adds 50–80 HP with no hardware. Stage 2 with downpipes adds 100–140 HP. Stage 3 turbo upgrades push 800–1,000 HP, and full-build Stage 4 cars run well past 1,000 HP with forged internals.
YPG Motorsport built the world's first sub-10-second W205 C63 — 9.97 seconds at 828 WHP on the M177 platform. That calibration expertise is built into every M177 product we sell.
Best for: Maximum aftermarket support, widest chassis compatibility, proven tuning path from 550 HP to 1,500HP+.
→ M177 Crate Engine Guide · M177 Short Block Guide · M177 Ported Heads Guide · M177 vs M178 Comparison
M178 — The Dry-Sump Sports Car Engine
The M178 shares the M177's 4.0-litre twin-turbo architecture but uses a flat-plane crankshaft and dry-sump oiling system. It's exclusive to the two-door AMG GT family: GT, GTS, GTR, GT R Pro, GT C, and GT Black Series.
The flat-plane crank gives the M178 a higher-revving, more exotic character — closer to a Ferrari V8 in sound and throttle response. The dry-sump system ensures consistent oil pressure under sustained lateral G-forces on track, and allows a lower engine mounting position for a lower centre of gravity.
The M178 tunes just as well as the M177 — same hot-V turbo layout, same ECU platforms, same forged internal upgrade path. The block castings and oil pans are different, so M177 and M178 parts are not interchangeable. Always confirm which engine you have before ordering.
Best for: AMG GT owners who want track-proven builds with the exotic flat-plane character preserved.
→ M178 Crate Engine Guide · M178 Short Block Guide · M178 Ported Heads Guide
Build Cost Comparison
| Build Level | M156 | M177 | M178 |
|---|---|---|---|
| Forged internals kit | $5,999 | $6,599 | $6,599 |
| Short block | — | $23,000 | $23,000 |
| Crate engine (complete long block) | From $25,999 | From $29,999 | From $35,000 |
| CNC-ported heads | Contact | Contact | Contact |
All YPG engine builds ship worldwide for free. No core exchange required — you keep your original engine. Build time is typically 7–21 days depending on specification and component availability.
Which Engine Should You Build?
Already own the car: You build whatever engine is in it. M156, M177, and M178 are not interchangeable without major custom fabrication. Check which engine your car has and order accordingly.
Choosing a platform for a new project: The M177 has the widest chassis compatibility, the largest aftermarket ecosystem, and the most proven tuning path. The M156 is the choice if you want naturally aspirated character. The M178 is the choice if you're building an AMG GT for track use.
Not sure which build level you need? Read: Short Block vs Long Block vs Crate Engine — What's the Difference?
Need help deciding? Contact us at sales@ypgmotorsport.com — we'll help you spec the right build for your car and your goals.
Frequently Asked Questions
Can I swap an M177 into an M156 car?
Not without extensive custom work. The engine mounts, wiring, transmission, and ECU are all different. It's more practical to build power on the engine your car already has.
Which engine makes the most power?
All three can exceed 1,500 HP with the right build. The M177 and M178 get there more easily because they're already turbocharged. The M156 requires adding forced induction first.
Is the M177 the same as the M178?
No. They share displacement and turbo layout but use different crankshafts (cross-plane vs flat-plane), different oiling systems (wet vs dry sump), and different block castings. Parts are not interchangeable. Read the full M177 vs M178 comparison.
Do I need a core exchange?
No. YPG does not require a core exchange on any engine build. Your original block stays with you.
What is the build time?
Typically 7–21 days depending on specification and component availability. Contact us for current lead times.