The bolts are "angle tightened", after getting them all snug with a torque wrench, to induce some initial stretch and "spring" in the clamping action. This is needed because the aluminum expands and contracts more with temperature than steel/iron. You really need to use new bolts and then "stretch" them the proper amount when assembling the head.

A copy of the factory manual for the mechanicals of this engine will be worth every cent of the approximately $30 it costs for this project. (If you don't already have it.)

I've seen several home made cam clamps following the operating concepts of the factory ones. One set was made using large, 5/8" dia threaded rod with the end turned and taped to fit the spark plug hole. I'm making some using 3/8" threaded rod with one end screwed into canabolized and taped spark plug housings. Some steel flat stock with holes will form the bridge pieces.

If you very carefully mark the cam to the pulley before you take things apart you should be able to get it together well enough. If desired you can always take it to the dealer for a final cam setting with the tool later.

Just some of my planning for changing my cams from the 180 HP versions to the 200 HP versions.
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'96 965 with 16' wheels at 114K. Had '85 745 Turbo Diesel for 200K.