The late model A+ head has bigger intake valves and is prone to crack between the seats. It's been pretty much covered here as for whats needed for a good LP head, look for no to very little guide hump in the exhaust port and those heads will also have a lesser guide hump in the intake as well, once you see "big hump" head and "lesser hump" head it will be rather obvious, a bad head and a good head flow about 10 cfm difference (which is huge with these engines), then once you've got a few good heads, you can also see flow numbers from one head to the next of +/- 5 cfm, James, when you find head/s you think will work, you're welcome to send to me and I'll flow them for you, I got data on probably 50 LP 1275 heads, so I know the sort of flow numbers we are looking for. I can tell you if you going thru alot of heads, its alot of work, you need to hone in on the ones you think are the good canidates and then disassemble them, degrease and then beadblast them and clean them again, just to get good honest flow numbers, they need to be clean, and not carbon filled.
As for as what makes a good LP head on a 1275, it for sure is not a casting number deal, it's more of casting flow/shift deal. I'm sure the same is true with the other LP cars as well, because I can remember 25 years ago, factory VW giving my SSC buddy different stock heads to put on his SSC car, that they had flowed and determined to be the cream of the crop.
