the cam dot and pulley dash line up, and everything looks in place, but its not starting, it cranks over and tries to start, but won't when I leave go of the key, any ideas?

getting a spark? fuel?

HT leads the right way around?

is it lined up with the bottom tdc mark? its all well and good having the cam in the rite place but if the rest of the engine is out it can stop it from starting.

All the plugs back in? I triple checked mine before i even turned it over.

Could be a rotor arm, my mechanic said that after one stressful day he had put everything together and it wouldn't start he was just about to pack up when he saw the rotor arm sitting in its packaging on the workbench, everyone took the piss for weeks.