i made 413/423 on a mustang with a kamak sts td06sl2-20gtx
stock block with cp drop ins, no serious head work (just a valve job and refresh), mbc, 21psi, 1000cc injectors, walbro 255, full exhaust (elh, catless dp, gs 38mm up, 3in catback)and other random supporting mods.
its not that hard to reach 400 on a 20g style turbo.
should have just waited to go on a computer and searched better. next time i guess...