I have semi torn down 1970 383 hp motor with1967 closed chamber heads and purpleshaft cam duration unknown.I also have a low mileage 1970's winnebago 440 motor turn key ready to drop in.The tranny is a 727 with a 3000 stall and a stage II shift kit .The rear end is a 456 gear 8 3/4 and it attached to a 1970 duster.The dilemma is witch motor should i choose considering the combo listed .I am leaning towards the 440 out of conveniance because it is ready to go but how will it perform?I want it to go pretty good..........any suggestions?