Possible cam install
Is this true.
318s get a little radical with a cam larger than .450 lift on 270+ duration, 360s get radical when you get up to .485 and 290+ duration, so a .450 lift and 270 degree duration in a 360 screams, idles pretty smooth and will get a little better mileage without any sacrifices.
This is form allpar.com
http://www.allpar.com/mopar/4bbl.html