The Edelbrock part 77485 Big - Block Chevy Victor Jr. 24deg cylinder head features an extra thick deck and extra material in the spring pockets for a heavy - duty casting that can be used with high - lift cam and heavy spring combinations. Edelbrock equips the complete 774815 cylinder head with a spring packages to suit hydraulic roller cams. The 300cc rectangle ports produce impressive flow and great power on competition big - blocks up to 510 c.i.d. with 4.310 or larger bore. Exhaust port exits are raised .534 to greatly improve exhaust flow and power.