difference with motors

Hi again,I was just trying to figure out what the difference is between a shovel head,a knucklehead,a panhead and ironhead.Is there a major difference between the engines or are they similar.Also what are the usual problems to look for with each of the motors if i were looking to buy one.
Hope someone can help.
Cheers

A lot of things different, a lot the same. 45º V-Twin, 2 cylinder air cooled, with low pressure, high volume oiling. Principle differences are the cylinder head design, barrells and displacement. The Knuckle has the most differences while the Pan and Early Shovel (through 69) are very similar. The '70 and later Shovels are referred to as Nose cone style instead of Generator style. This is due to the cam being in a cone on the right case rather than the generator style where the cams lived behind the flat cam cover. A lot of nostalgia builders are now utilizing reproduction Knuckles, Pans etc as it goes with the Chopper craze. There are other similarities and differences and I would suggest getting a book that discusses the engine line.

Thanks CD for the brief info.Is there a specific book on the motors that you know of that i should look for as the best reference etc.
Cheers

Check out HD online

now forgive me for butting in where I am not needed, but have you checked the history section of harleydavidson.com? Go to the USA site and products then engines. Hall of engines. There will not be everything you need to know there but a start. There are so many books about HD and motors if CD does not have anything try searching Amazon. There are not a lot of MAJOR differences in the motors but with each motor there were a few changes for the better. At least that is the way I see it.