Pair (2) Loaded Cylinder Heads GM Chevy SBC 305 5.0L Vortec Swaps 12558059 520 For Sale

Looking for a high-performance upgrade or heavy-duty replacement? This PAIR (Set of 2) of brand-new cast iron loaded cylinder heads is the perfect choice for GM 305 5.0L Vortec engines, Classic Small Block Chevy (SBC) Vortec Swaps, RVs, and Industrial power units. Fully assembled and ready to bolt on straight out of the box!

• Airflow Optimization: Precision 3-angle valve seat machining blended to the bowl area delivers superior volumetric efficiency and extra throttle response.
• Hardened Seats for Longevity: Built with induction-hardened valve seats to easily handle sustained high-load demands in towing, RVs, and industrial equipment.
• 58cc Chambers: Maintains optimal 305 compression ratio without risking valve-to-cylinder clearance issues.

• Trucks, Vans & SUVs: 1996–2002 GM Chevy C1500/K1500, Express, Savana, Tahoe, Suburban, Sierra, Yukon with 5.0L L30 engine (VIN R).
• Hot Rod & Classic SBC Swaps: Popular upgrade for vintage Chevy trucks, muscle cars, and street rods swapping to Vortec 8-bolt intake setups.
• RVs & Industrial Units: Excellent for Class C RVs (GM Cutaway chassis), step vans, and stationary GM 5.0L power units/generators.
• OE Reference: Replaces OE # 12558059, 12552520, 12557113 (Casting # 059, 520, 113).

• Double-Wall Packaging: Packed in heavy-duty cardboard boxes with high-density custom foam for complete transit security.
• Express Courier Shipping: Dispatched via FedEx / UPS Ground. Shipped in TWO separate boxes due to total product weight (~90lbs/pair).

• 1-Year Protection: Backed by a full 1-Year Limited Warranty covering manufacturing defects.
• Fast Customer Service: Customer messages answered within 24 business hours.