C-AHT413 & C-AJJ4083 – CYLINDER BLOCK INFO
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...