Hammer right should be fine to do the block of the engine.
Couple of things worth noting before you get out there with your paint and brush.
Make sure to totally clean everything before painting as any grease and dirt will shorten the amount of time the paint will stick to the block ie flake.
Dont paint over any joints, bolts or anything that might have to be removed at anypoint in the cars life.
Mask up any and everything you dont want paint on as paint does have a habit of flicking on things it shouldnt.
It might pay you to remove as much out of the engine bay as possably and put one side of the car up on a high kerb allowing access to hard to reach areas that can be seen but not reached with a brush