What Cam?

I use this one in a very similar engine with their recommended springs, retainers and locks. http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=625&sb=2
Be careful with lift as stock 318 heads wont take much more than .450" depending on seal used.

Coronet 500 has this good one above and i'll throw out one....

http://www.summitracing.com/parts/SUM-6900/