Solo,
I would take the 350's over the 400 too! You didn't say if the 350 blocks were 2-bolt or 4-bolt mains? Building a stroker motor then the 4-bolt is the only way to go! Also you need to be thinking about what the cc's are of those heads. You don't want too high a compression ratio so the bigger cc heads will help reduce the compression ratio. My choice of heads would be the 194 fulie heads but that will probably already put you up into the 10 or 11.5:1 compression ratio. I would spend the extra money since your building a stroker motor and wisely invest in the screw in studs and guide plates. Don't forget the fulies don't have provisions in the heads for brackets to bolt up...just something to keep in mind as an added cost for different brackets.