Dart IMCA Hobby Stock Cast Iron Small Block Chevy Cylinder Head

IMCA Approved Stock Replacement Dart Cylinder Heads These Dart IMCA Approved cast iron Small Block Fits Chevy cylinder heads are approved stock replacement heads for Hobby Stock, Northern & Southern Sport Mod, and Stock Car classes (using the 500 carbuertor). We begin with a Dart 10024360 Iron Eagle S/S 165 casting. Each head is engraved and serial-numbered to conform to IMCA rules. After extensive research and development regarding the airflow capabilities and performance characteristics of this cylinder head versus previous models, IMCA approved this Speedway Motors-exclusive IMCA Dart cylinder head and it's available for fast shipment in bare or assembled configurations. Featuring precision cast ports and chambers, they have outstanding air flow. Assembled versions have optimized valve sizes for maximum performance within IMCA rules. (BARE) - Bare Cylinder Head (HS) - IMCA Hobby Stock Heads (SM) - IMCA Sport Mod Heads (Northern and Southern SportMod) (SC) - IMCA Stock Car Heads (SCBARE) - IMCA Stock Car Bare Cylinder Heads Complete assembled versions include high-performance springs, 1.94"/1.50" standard length stainless steel valves, 7 degree locks and steel retainers with 3-angle valve jobs. Sport Mod and Stock Car versions includes high-performance COMP Cams valve springs and handle 0.550" net valve lift, with Ferrea tool steel retainers. Stock Car versions are .080" max flat milled w/ intake surface corrected to max out the compression rule for the IMCA Stock Car. Hobby Stock heads feature Speedway Motors USA-made high performance valve springs 180671515. Approved for IMCA Hobby Stock, Sport Mod and Stock Car classes (using 500 carb) as of 4/27/2020. Assembled heads take approximately 1-2 days for assembly and will be shipped out promptly afterward. Approved for IMCA Hobby Stock, Sport Mod and Stock Car classes (using 500 carb) as of 4/27/2020