The new ALL AUSTRALIAN Austin Healey 100/4 aluminium cylinder head is now available.

We at HSD have been developing this head for quite a number of years. Cast, machined and assembled all in Australia to be a direct replacement for the 100/4 with the ability to use all stock manifolds, rocker gear or we can supply a complete roller rocker assembly as well as a unc-bsf stud kit which is supplied with each head (for standard rocker gear and bsf nuts)

Our heads are not only lighter due to being aluminium with better cooling ability creating a cooler combustion chamber they have significant performance gains utilizing 1.760 intake valves and 1.520 exhaust valves with out of the box gains of 10cfm over standard heads, although that doesn’t sound like much these heads are cast thicker in areas for the people that want to go the extra mile and heavily port with oversize valves.

Yella Terra roller rockers made specifically for the Austin Healey 100/4 and are a bolt on item