7 1/4 rearend

i had one added 410 gears to it and beat the tar out of it and it woildnt break just makemsure u put a street tire because sticky tiremwill kill it..and itmwas behind a 509 cammed 360


7-1/4" or 8-1/4"? I have never heard of 4.10 gears being available for the 7-1/4"?