Cast Iron, 119cc combustion chamber, 308 or 345cc intake volume. Can be used with Mark IV and Gen V & VI with proper head gaskets. Bare assemblies only. Select port and intake valve size. Exhaust ports are 1.880”. If you don't see what you're looking for please call or e-mail us. Phone: (480) 753-0208 Fax: (480) 753-0216 Hours: 8am - 5pm M-F Mountain Standard Time