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Built on Ford Performance’s BOSS 351 block, the X-Head 427 crate engine is engineered and built to deliver a strong and flat torque curve.   Like all of the Ford Performance crate engines, the X427 is hand assembled with nothing but the best new parts from aftermarket companies like Mahle, SCAT, Clevite, COMP, PAC, Fel-Pro and more. The engine internals are designed for performance including; forged crankshaft, forged I-beam connecting rods with floating piston pins and a high performance oiling system. Built with the BOSS 351 block and the legendary X-Heads, X427 fits many of the vehicles originally built with a 351 Windsor engine.  With 427 cubic inches, 450 horsepower and 520 lb. ft. of torque, the X427 delivers tire-smoking acceleration for street rods, kit cars and muscle cars. It also delivers power and torque for light duty pickups and SUVs.

450 horsepower @ 5600 rpm

520 lb-ft torque @ 4500 rpm

  • Engine type:  351 based small block Ford
  • Displacement (cu in): 427
  • Bore x stroke (in): 4.125" bore x 4.00" stroke
  • Block: Boss 351 9.5” deck
  • Crankshaft: SCAT® Forged Steel
  • Connecting rods: SCAT® forged steel H-beam connecting rods and ARP® bolts
  •  Pistons: Forged Mahle® w/ floating wrist pin
  • Camshaft type: Hydraulic Steel Billet Roller
  • Camshaft lift – intake/exhaust (in): .563"/.584"
  • Camshaft duration – intake/exhaust (@.050 in): 232°/240°
  • Cylinder heads: Ford Racing Aluminum 64cc Chamber Cylinder Heads - M-6049-X306
  • Valve size (in): 1.94" intake valves and 1.54" exhaust valves
  • Valve Springs: PAC® 1219X Ovate Beehive
  • Compression ratio: 10.5:1 (nominal)
  • Rocker arms : Roller Rockers
  • Rocker arm ratio: 1.60:1
  • Vibration Damper - Ford Performance SFI Approved - M-6316-D302
  • Valve Covers: "Ford Racing" cast aluminum black wrinkle finish "427 Cobra" script - M-6582-W427B
  • Oil Pan: Steel with deep front sump pan with windage tray / scraper - 9 quart capacity
  • Water pump: included long type - standard rotation
  • Distributor: not included. MSD® distributor #85840 recommended (dist. modifications for intake clearance necessary)
  • Recommended fuel: Premium Unleaded
  • Maximum recommended rpm: 5,600 rpm
  • Internal balanced. Use neutral balance flywheel
  • Front sump pan fits most kit cars
  • New block, oil and water pumps, performance oil pan and high-performance harmonic balancer
  • Can be used in kit cars, street rods, Mustangs, Fox-bodied cars and trucks
INSTALLATION NOTES: Some or all of the following items may need to be changed from your original engine or modified for proper installation: 
  • Depending on your application, a different timing cover, water pump, performance oil pan and pickup may be required.
  • Engine has a performance front sump oil pan and pickup, standard rotation timing cover, standard rotation water pump and non-EFI valve covers.
  • Timing cover will work with most standard rotation water pumps
  • Fuel pump eccentric M-6287-B302 installed, allows use of mechanical fuel pump
  • Valve covers M-6582-W427B will fit most non-EFI applications. Other, optional valve covers sold separately.
  • The damper M-6316-D302 may require a spacer for pulley alignment.
  • Flywheel not included, use proper neutral balance flywheel
  • Intake manifold not included
  • Includes intake gaskets, as well as pilot bearing
  • Firing order 1-3-7-2-6-5-4-8 (5.0L HO and 351W firing order)
  • Steel distributor gear required
  • Shipping weight approximately 570 lbs
  • Built with current available parts. Photo and specs may vary.
  • Engine installation tuning tips at performanceparts.ford.com
Part Type
Engine: Complete Engines
Warranty Availability
Package Dimensions
36" x 39" x 36"
Package Weight
520 lb(s)
UPC Code
Country of Origin
United States