I built the 318 in my 72 duster years ago and used a short duration erson cam with about 450 lift at first. A performer intake and an eddy carb.Blackjack headers and a head shave and plunge cut under the 1.88 valves i added finished the package. Ran 9.0 1/8 mile untill I found an 8.75 and added 3.91 gears and a b&m holeshot converter. That change netted about 4 tenths and I was running 8.60s and would run with the 350 z28s. Gained a lot of respect when they realised it was a measly 318