I'd get the 318, and send the cam in your current 318 out to bullet to get reground using their HR259/316 lobes for intake and exhaust, and put that into the new motor, reusing the lifters, pushrods, etc.
1976 Spinnaker White Plymouth Duster, /6 A833OD 1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!*** 2011 Toxic Orange Dodge Charger R/T 2017 Grand Cherokee Overland 2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
