Help me put "587" heads on a 318

Looking for some advice on this setup.. I have some heads from a '73 340 that have been laying around in my garage for a while, and want to put them on my 318 that's in my '68 barracuda.. I've done quite a bit of reading on this, sounds like I need to mill 40 to 50 thousandths off the bottom of heads to raise the compression... the heads could probably also use a freshening, some have recommended stainless valves.. I want to do what's best, but also I'm on a pretty tight budget.. I'm fairly new to engine work especially with mopars, so what should I tell my machine shop to make this happen without breaking the bank?