Big Block 516-v-452 head which one would you pick

I am in the process of putting a 440 in my dart which has a set of home ported by me 452 heads. Which i did not do a very good job at. they have been gone through by a machine shop new guides stock size valves, keepers, retainers.and springs to match my comp 305 cam. Ok i found a set of 516 heads with aftermarket 214,1.81 valves, keepers,retainers and springs good to 600 lift. the only porting they had done was some bowl work.I can get them for 450 pluse shiping. does that sound like a good deal and will i see any performance gain over my 452 heads? I really want to get some Edelbrock heads but can not afford it right now. Thanks Mopar658)8)