info need on identify ls3 or 4

[nova69]

bought a ls engine out of what im told is a 5.3 from a trailblazer. i want to make sure its not a 4.3 i dont have a vin just engine on the heads it has a 799 on the end. where would say on the block thats guys

[Kenova]

If the engine is from a Trailblazer there will be a hole or tube through the oil pan. This accommodates the steering linkage.
The 4.8 engine was never used in the 'Blazer and the 5.3s that they used have aluminum blocks.
Check with http://www.ls1tech.com/forums/ for info on your head casting number.
Ken

[nova69]

hey sorry about the grammer. thanks for the info