Is there any casting number or part number wich will show the engine is LS6 ? If so where ?

 

Casting # on the pass side head should say 243. It will also have the LS6 valley cover.

 

are you just talking about finding out if you have an ls6 block or entire motor?

if block then look at the back driverside and there is a casting number '12561168' is the ls6 casting number, anything else is an ls1 block.

if motor, check casting number on block and it should have ls6 heads which have a 243 casting number on them.
also will have an ls6 intake.

 

Thank you!!

 

A true LS6 will have the block, heads with sodium valves, cam, and intake.
You can have an LS1 with an LS6 block
You can have a modified LS1 with an LS6 block and the LS6 intake (241 heads)
You can have a modified LS1 with an LS6 block, LS6 intake, and 243 heads (but not the sodium filled valves or LS6 cam)

So I guess the question is how much of an LS6 do you want?

 

LS1 blocks have bullseyes cast in on the front edge along the top. LS6 blocks do not. Easiest way to tell, if the engine is in the car. LS6 heads can be added, so can a valley cover. Look for the bullseye marks or the part number to be sure.