looks like they are basically a ported 452...
cylinder head technical specs:
intake port flow (at peak ~600 lift): 290cfm @ 28" of water ]intake port cc: 212cc* intake valve head size: 2.14" intake valve stem size: 11/32", undercut near valve head. intake valve guide type: .530" od manganese bronze intake valve seals type: positive locking type, maintains contact at all times with the valve and guide, reduced diameter compatible with most dual valve springs. intake valve type: 1 piece forged 21-4n stainless, swirl polished heads, hardened tips. intake valve locks 7 degree, single groove, chrome-moly steel, case hardened. Recommended for maximum .510" lift. exhaust port flow (at peak ~600 lift): 220cfm @ 28" of water exhaust port cc: 72cc* exhaust valve head size: 1.81" ]exhaust valve type: 1 piece forged 21-4n stainless, swirl polished heads, hardened tips. exhaust valve locks 7 degree, single groove, chrome-moly steel, case hardened. Recommended for maximum .510" lift. exhaust valve stem size 11/32", undercut near valve head. exhaust valve seals type: positive locking type, maintains contact at all times with the valve and guide, reduced diameter compatible with most dual valve springs. exhaust valve guide type: .530" od manganese bronze valve spring type: single with damper. Recommended for maximum .600" lift. valve spring closed (seat) pressure: approx. 130 pounds @ 1.875" installed height valve spring open pressure approx. 330 pounds @ 1.275" (.600" lift.) valve spring inner diameter: 1.050" valve spring maximum lift: .600" valve spring coil bind height: 1.130" valve spring outer diameter: 1.550" valve spring free height 2.400" valve spring installed height: 1.875" valve spring wire diameter: .202" valve spring number of coils: 5.5 deck thickness: .625" chamber volume: 80cc* chamber type: closed (with quench surface) weight (bare): 22 pounds weight (assembled): 29 pounds aluminum type a-356 *due to normal casting processes such as core shift, etc, all cc volumes listed are approximate and subject to normal variation.