You can go thicker on material and add lightness with holes
Heavy (for a 4 cylinder ) all cast cam in head Opel engines use 2-3mm and no thicker for the 6 cyl which was same but 2 more cylinders / near 50% heavierpersonally they should have been made from least 5mm thick for that little 4 cylinder.......
these will def fracture.........sorry.......
probably one of the best uses for a Cinasuim adjustable spanner I have ever seen .well at least there adjustable = {universal ) or were
Brilliance.