When I talked to my friend earlier in the year about porting the head I have on the bike now, he was telling me about all the warriors he used to build untill the 450's came out and they went to wind. The last one he can remember REALLY building was a big bore stroker and it topped out around 512cc. Now, this was a while ago, so he was pretty certain that it was 512 or damn freakin close. Said that with a 16tooth front and stock rear it would wheelstand in 5th!