302 heads for 318

Thanks for all the advice! I'll just wait to gather the all the parts then put them on. Where is the best place to get these heads? Junkyard? I was going to get them from a local O'reilly's for about 250 a piece with a $65 core charge, everything thing is included but I feel like it's a bit pricey. I have checked the local junkyards and haven't found any small block dodges to scavenge the parts from.