Designed for competition 351 Windsor Ford V8's from 1969 and later with the following heads: Edelbrock Performer RPM heads #60259, Victor Jr. heads #77169, Victor heads #77219 or similar heads. Two versions available: #2980 fits SVO blocks with a 9.2" deck height and #2981 fits standard 351W blocks with a 9.5" deck height. Ideal for both oval track and drag racing engines operating between 3500 and 7500 rpm. Runners have a 2.70 square-inch cross sectional area. Carburetor Recommendations: Any size or type of carburetor class allows. Installation Notes: Recommended intake gasket: Edelbrock #7220 or Fel-Pro #1262. Manifold height: #2980 A-5.59", B-5.59"; #2981 A-5.75", B-5.75".