My LS-won

I need help. I've been searching for hours and find the same info over and over. I have a 454 bbc crate motor, bought it off some old man for $1,200. It came with no papaer work, so no spec sheet. The casting number is 12550313. I already know its a Gen 4, 4.25 bore 4 bolt main, one peice rear main, I want the HP and TQ numbers. Searched for hours and for some reason the casting # is diff form the GMPP part number.

here are all the i.d. numbers on the block. 12550313 ... L089... and stamped ontop of the even number clyinder deck is TE09m6bo..

Thank you for your time and paitence.

9000th01ss

iTrader: (10)

One piece rear seal is not a Gen 4 (really Mark IV) Going by the casting number you have a Gen V or Gen VI.
Use something like google to figure out the rest, unless someone on here knows the numbers off the top of their head.

torquejunky

iTrader: (10)

12550313...454.......91-up...4-bolt, Gen.V crate motor, Gen. VI 4.25" bare block
power ratings are going to depend on heads, cam, intake, etc.
hope that helps.....