1974 valiant stalls in gear 225 automatic

update . replaced plugs and all old ones looked ok visually . brown residue , gaps were good . after that i drove the car for 10 miles . heavy on the pedal . when back , the idle rpms were up a bit from before , and the car stayed running even idling in gear , though it seemed low on rpm . after i got back i set idle rpm to about 750-800 and even though when put into gear it seamed really low rpm and really quiet . stayed running . short drive . seems ok , just maybe still to low when in gear . not sure . tried two different timing lights but couldn't get a reading . just flashes no line . ran great on the 10 mile though . really great . just the low rpm at stops . tried the carb cleaner again at base of carb . rpms went up a tiny little bit . then sprayed down the carb and it didn't raise rpms this time . it wanted to cut out from the spray .