The 1bbl will work fine if properly jetted. You will want to redo the head(bigger valves and some port work Shave it)next. THEN move on to a 2 bbl or small 4 bbl.
Frank
Frank not sure what your experience is,but wih my 67, stock 225 with a clifford full length header and a 1 bbl it didnt work no matter what jet I used.Even a 61 jet in the 1920 did not work.Idle was great,stinky but ran smooth,as soon as I would breathe on the throttle it would go lean and surge.I would recommend some kind of tune able 2 bbl or 4 bbl.Just a jet change wont cut it.