When using a new unmachined cylinder block, the block face can be machined to within 0.25”(0.635mm) of the piston crown at T.D.C. This will give approximately 12.5:1 on a 1293cc engine with 13cc chamber.

If the cylinder block being used has undergone machining to bring the piston to within 0.10”(0.254mm) of the block face, machining the piston crown is necessary.

Providing forged pistons are used 0.015”(0.381mm) can be removed with safety by machining the total of the piston crown. Alternativley, machine the piston using a cutter of 1.625”(41.275mm) with a radius of 1/16” (1.6mm) 10mm Sparking plugs are required for this head.

Three different heat ranges are available.
Hot plug C-AHT412 (G63) will be suitable for warming up, rally and road use;
C-AHT435 (G59R) will be better for circuit racing using carburettors.
For circuit racing with fuel injection it may be necessary to fit a colder plug, C-AHT413 (G56R)

Four Amal carburettor kit C-AJJ4083 is complete with carburettors, inlet manifolds and linkage is suitable for use with this cylinder head.