I have heard that the 11-14s are around 480 a 15 is supposed to be around 540 hp but I haven't seen an actual on paper difference. I know my 15 is very strong but I have no experience with the 11-14s.
530-540 is what I advertise on 15's. The 11-14 seem to do about 470-490 depending on how strong the factory pump is. My 11 w/ a 15 charger swap did 507, so there is clearly more in the 15 pump volume wise.