A selected range of modified cylinder heads are available to suit a wide variety of applications. All port and chamber modifications are carried out by experts to current state of the art specifications. Therefore, actual specifications may alter slightly as gas flow and port velocity efficiency improvements are developed. Where large bore heads are used on small bore engines (i.e. 12G940 casting on 948/1098cc block), it is necessary to check full lift of exhaust valve, and pocket the block as necessary. All heads have EN214N steel valves, hidural valve guides and hi-grade valve springs. REMEMBER: Highly polished ports reduce atomization and DO NOT increase flow.

SPEC: 35.6mm In. 31mm Ex. Combustion Chamber Volume 21cc
12G940 casting recommended for most road use engines having higher velocity ports to retain torque.

SPEC: 37.2mm In. 29mm Ex. Combustion Chamber Volume 24cc
12G940 casting. Larger ports and inlet valve make this suitable for highly modified road engines and especially the big bore 1380/1400 type.

SPEC: 37.2mm In. 31mm Ex. Combustion Chamber Volume 21cc
12G940 casting. Very modified head suitable for race applications and extensively modified big bore and long stroke engines. Exhaust valve is offset to minimize cracking between the valves

SPEC: 31mm In. 26.4mm Ex. Combustion Chamber Volume 24cc
It has the biggest valves fitted that produce maximum flow figures, and is suitable across the entire small bore range from relatively standard to fast road applications.

SPEC: 33.3mm In. 29.2mm Ex. Combustion Chamber Volume 24cc
12G295 casting. The ultimate small bore head. Modified to suit all fast road/rally engine specifications.   Suits race small bores.

Lead free head. As C-AHT87 but with exhaust valve seat inserts.

C- AHT134
SPEC: 35.6mm In. 29.2mm Ex. Combustion Chamber Volume 20cc
A budget 12G940 head using standard iron valve guides and standard heavy duty material valves. Ports and chambers are modified for maximum efficiency considering the valve sizes. This head is suitable for fast road applications where a limited budget is available.

SPEC: 37.2mm In. 29mm Ex. Combustion Chamber Volume 17cc
Same as the C-AHT221 but has been fully flow tested and balanced. It has longer valves (.140" longer) & special springs (with rotators) to work better with high lift cams.