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Edelbrock RPM Xtreme™ Cylinder Heads for Small Block Ford
+21 HP / +13 Ft/Lbs. of Torque over the Competition!

Edelbrock RPM Xtreme series cylinder heads for S/B Ford, #51259, are CNC ported where it counts for maximum air flow ultimate performance. Engineered and manufactured using the best combination of as-cast port design and CNC technology, RPM Xtreme heads are CNC ported in the critical areas (combustion chambers, intake entry, exhaust exit and intake/exhaust bowls) for improved air flow and overall performance. RPM Xtreme heads are ideal for high-performance street and entry-level race applications. These heads are sold complete with high-quality conical (beehive) springs, 8mm stem stainless steel valves, and include heli-coil inserts in the exhaust flange and rocker stud bosses.

Dyno testing on a stock 404 CID Windsor engine with the addition of Edelbrock RPM Xtreme Series heads #51259, Edelbrock RPM intake manifold #7181, roller cam (.576"/.600" lift with 242/248 duration @ .050) and Edelbrock 800cfm carburetor #1412 resulted in an impressive 508 horsepower @ 6500 rpm and 504 ft./lbs. of torque @ 4400 rpm - that's 21-horsepower and 13 ft/lbs of torque increase over a competitors fully CNC ported head!

All Edelbrock cylinder heads are cast and machined in Edelbrock's own California facilities for absolute consistency and quality control. Available for now for small-block Ford, GM LT4 & LS-Series and coming soon for small-block and big-block Chevy, and big-block Chrysler.

    Features Include:
  • CNC porting in critical areas that improve air-flow and performance
  • Fully CNC machined 59cc combustion chambers
  • 18-degree valve angle
  • 5/8" thick deck for extreme durability
  • CNC profiled185cc intake ports flow 265 cfm @ .600" lift
  • CNC profiled 75cc exhaust ports flow 209 cfm @ .600" lift
  • Lightweight 8mm stem valves (2.02" intake and 1.57" exhaust)
  • Conical (Beehive) springs for consistent valve train stability
  • #51259 (complete)

For more information visit: RPM Xtreme S/B Ford Cylinder Heads

About Edelbrock, LLC

Founded in 1938, Torrance-based Edelbrock Corp. is recognized as one of the nation's premier designers, manufacturers and distributors of performance replacement parts for the automotive and motorcycle after markets. For more information please visit us at