M20 Race Stroker Engine

The BimmerHeads Race M20 Stroker Long Block is our Stage 3 flagship — the most capable M20 we build, and the engine we’d spec for any serious high-horsepower or forced induction build.

Built to order, every Race engine comes standard with BimmerHeads performance dual valve springs and KM Cams forged steel rocker arms. Every Race engine also receives combustion chamber polishing by hand — a step reserved for our Stage 3 build only.

Every Race engine is run-in and tested on our custom-built engine run stand before it ships — we break in the camshaft, check for oil leaks, and verify quality control using Motul Break-In oil and Mahle oil filters. We never slap something together just to send it out the door.

Choose your camshaft, valve, and stroker size configuration above — not sure which combination is right for your build? Contact us and we’re happy to help.

Every Race engine includes a fully rebuilt Race spec 885 cylinder head receiving:

• Cleaning & pressure testing
• Resurfacing
• Extensive porting & polishing by hand
• Combustion chamber polishing by hand
• New Supertech valves
• New Supertech valve guides
• New performance valve seals
• New camshaft o-ring & seal
• New BimmerHeads performance dual valve springs
• New KM Cams forged steel rocker arms
• New rocker arm hardware & eccentrics
• New intake manifold studs
• New thermostat housing studs
• New exhaust manifold studs
• New valve cover studs

Every Race engine bottom end receives:

• Cleaning
• Magnaflux block to check for cracks
• Deck resurfacing
• Cylinder boring & honing
• New CP-Carrillo forged pistons, wrist pins, piston ring set, and wrist pin clips
• New Molnar H-Beam connecting rods — 4340 billet, ARP2000 bolts, shot peened, bronze wrist pin bushing, ±.0001" tolerances, USA-made
• New ARP cylinder head stud kit
• New ARP crankshaft main bolt kit
• New ACL Race crankshaft main bearing set
• New ACL Race connecting rod bearing set
• Reconditioned original BMW crankshaft (2.8L) or forged original BMW crankshaft (2.9L and larger) — every crankshaft cleaned, inspected, and micro-polished before assembly
• Crankshaft seal adapter sleeve, OEM crankshaft bolt, and machined washer (2.9L and larger)
• New engine oil pump
• New engine oil pan
• New magnetic oil drain plug
• New oil pressure switch
• New Gates Racing timing belt
• New billet timing belt tensioner
• New timing belt tensioner spring
• New timing belt tensioner stud
• New intermediate shaft gear
• New water pump
• New freeze plugs
• New engine block coolant drain plug
• Satin black engine block paint
• Ultimate head gasket set
• Bottom end gasket set
• New NGK spark plug set

Camshaft options:

• Regrind 280/274 — dual pattern — ground on a used OE BMW core with different intake/exhaust duration for stronger pull under boost. The go-to grind for forced induction builds.
• New 280/274 — same dual pattern 280/274 grind on a brand new core. For those who want the 280/274 grind without a reground cam.
• Regrind 284 — higher lift and duration for serious builds. Recommended for stroker M20s with higher compression. Strong top-end pull with a noticeable idle lope.
• New 284 — same 284 grind on a brand new core. For those who want the 284 without a reground cam.
• Regrind 284/280 — dual pattern — maximum aggression, with higher lift and duration on both lobes for serious horsepower under boost.
• New 284/280 — same dual pattern 284/280 grind on a brand new core. For those who want the 284/280 without a reground cam.

Valve options:

• Standard Size Supertech — 42mm black nitride intake / 36mm black nitride exhaust. The valve set behind every BimmerHeads M20 885 head build.
• +1mm Supertech & Machining — 43mm black nitride intake / 37mm Inconel exhaust. Head is machined to fit the larger valves. Choose this option when your build calls for maximum flow.

Stroker size & turbo upgrade options:

Standard compression ratio: 10:1 (naturally aspirated) / 9:1 (turbo upgrade). Available in 2.8L, 2.9L, 3.0L, and 3.1L. Custom compression ratios available — note in order comments at checkout.

• Turbo Upgrade — available on any stroker size. Includes heavy duty pistons and wrist pins along with an upgrade to the Power-Adder version of our Molnar H-Beam connecting rods.

Each engine is built specifically for your order — no cancellations are accepted once placed. Allow a minimum of 16–17 weeks production time. Please specify your water pump fitment in the order notes at checkout — early (1987 and older) or late (1988 and newer).

Price includes a refundable $700 cylinder head core charge and a refundable $300 engine short block core charge ($1,000 total). Once your BimmerHeads engine arrives, use the original crate to return your core engine. Cores that pass our inspection and testing receive a full $1,000 refund. If the camshaft is unusable, the crankshaft is scored, or repairable damage is found, we will contact you before any deductions are made. Return freight is the customer’s responsibility.

Freight is billed separately. Due to the variables in engine freight cost, shipping will be invoiced once your engine is complete and ready to ship.

Our Spec Sheet has the installation references you’ll need — valve clearances, torque specifications, oil recommendations, and break-in instructions.

This is our best M20 work, and we treat it that way. Every Race engine is assembled with the level of care this build demands — run-in on our custom stand, broken in on Motul Break-In oil, and inspected before it ships. If it doesn’t pass, it doesn’t leave. That’s not a policy — it’s how we work.