Thinking about going 5.9

Ok I've been thinking about going with a 5.9.my 73 duster currently has a stock 318 with performer intake.570 street avenger
Dual 2" exhaust stock manifolds.i love my 318 but always want more power
Local junkyard 318/360la are scarce.but 5.9 magnums are everywhere.i can get them for maybe $200.add warranty.and could bring parts back to swap if things are bad.i dunno of I want one all stock at first.and build another one with stuff done too it later.because I'm thinking about going bigblock in future.unless I'm happy with magnum.at min.first magnum will have a magnum rpm airgap.and use the 570 street avenger.because I'm sure more cam will require bigger carb?8 also have new set of hooker 5901 headers and 2 d8ngle chamber mufflers.plan is to use all stock untouched bottom end.i think that going from stock to big performance cam may cause issues at first.but maybe less likely if just using it all stock except with rpm intake and 570 street avenger.looking for help.before I go bigblock haha.car is currently my daily driver.figure stock magnum or at least a stage 1 cam from one of those companies I see on this site.