Help on 318 purchase - Newbie mechanic questions.

I dont know much about casting numbers but found this online

http://www.stockmopar.com/mopar-engine-casting-numbers.html

I would say that 400.00-500.00 would be realistic idea for a basic ( semi to complete)rebuild kit but recommend researching a good machine shop to check all the tolerances and they can prob get you the rebuild kit as well.