We're WAY past the day when you can find a "better deal" on good SBC cylinder heads. 882's are basically "door stops", and I don't care what you read anyplace on the NET they aren't worth putting one minute of you time or one cent of your hard earned cash into. I've been building and dynoing SBC engines for decades and they will not make the grade anyplace. The 624 counterparts to the 882's flow a little better, but the crack rate for them will be nearly 100 percent as they are paper thin and the factory got them too hot when induction hardening the seats IMHO.
The last of the good castings were 993's in 1973, and they had induction hardened seats so many of those will be cracked. The good heads from 1970-72, 441's, 336's, 487's are "soft seat" other than a few very late 487X castings so they will need hardened exhaust seats installed for this new fuel.
The "holy grail" heads from the 1960's will lack accessory bolt holes, 291's, 461's, 462's, etc except for the excellent 041 and 186 castings from 1969 and 1970. Even those are going to need hardened seats installed.
Also keep in mind that all the good early heads with few exceptions are pressed in studs and the valve guides will be worn some.
By the time you buy good factory castings, have a full set of good guides installed, machined for screw in studs/guide plates, hardened exhaust seats, good one piece valves, springs, retainers, locks, etc you could have bought a set of much better flowing heads with modern combustion chambers, much thicker material, hardened seats, one piece stainless valves, etc, etc, etc for less money.
My personal favorites are the World Products SR and Sportsman heads, but there are a LOT of companies in that market with similar products for even less money, and all of those heads are going to be superior to any factory head even after you are done spending a ton of money on them....FWIW......Cliff