You don't say what type/size compressor you have, but a touch up gun with a 0.8mm nozzle would be about right.
That type of gun would give paint delivery not so different to an aerosol but in a flat pattern not conical.
Most general use body shop guns are 1.2 or larger. these will deliver to much paint unless used with great care. On an engine which has lots of nooks and crannies a smaller gun will allow for a little more build up in the corners without leaving runs all over.
Saying that, smaller parts you intend to spray you could use an air brush with a 0.5 nozzle and get a reasonable spray pattern and finish.
This is all very subjective and although I have done a small amount of paint spraying I am by no means an expert.
John
Edited By John Bromley on 22/11/2014 10:30:00
Edited By John Bromley on 22/11/2014 10:37:32