As in title, my 420g turns over nicely it then basically locks up momentarily then starts. Im told its a timing issue that can be adjusted via the distributor? Is this the case and if so how is it done? Any advice would be greatly appreciated.

 

If timing mark on front crank pulley, loosen base of distributor and use a timing light and align the pointer to the pulley mark and advance or retard by turning distributor. If timing mark is thru a hole in the flywheel housing on top behind head. Turn engine until you see marks and put some white paint or chalk on marks and do the same. Then tighten distributor base.

 

The timing is too far advanced, the car is firing too soon. You need to take the distributor cap off, watch which wat the rotor runs as the engine rotates, and loosen and turn the entire distributor the same direction as rotation by a few degrees. Re tighten, put the cap on, try it. Or do it right with a timing light.

 

Starter motor could also be on its way out.