I've heard that some models of Suzuki trucks/car are immune to timing chain/belt break.Has anyone know if this is actually the case?

l do not think any engines by any manufacturer r immune to timing belt / chain breakage. What u have heard is probably that if the belt does break it will not cause damage to the cylinder head, pistons & valves.
On many engines, there is little clearance between the piston top & valves when the piston is at the top of its stroke. If the cam-drive breaks, then the valves r left open as the piston comes up & CRUNCH! It squishes them back up into the head & causes damage. The Suzuki engines may not be affected by this due to the valves not penetrating far into the combustion chamber.

My ford Zetec engine was quite happy with me turning the crank by hand with the cams locked so l could set up the timing belt properly.