I recently picked up a set of heads, thinking they were LS1's. Just to be sure, I looked up the numbers but they did not match LS1 castings. A reliable source says they are "the mexican version of LS6 heads." What does that mean?

And if anyone could verify that this is what they are, the numbers are:
4229L3472497
0422911238322825
I don't know which number you may need. Also, on the outside of the head, where LS1 heads have a number 241, these have a 799. Any help is appreciated.

 

I can't find the # you posted,but the ls6 heads have a "D" shaped exhaust ports and the ls1 has an oval-shaped exhaust ports.The Mexico,Silao plant built only the 5.3L truck engines Gen.lll V-8,I think that is right. Hope this helps you.

 

the 799 number is the casting for the early version of LS6 heads as found on the 2001 ZO6, sometime refered to as mexican casting LS6 heads. you have true LS6 heads.

 

Thats what I wanted to hear.
Thanks for the replies.

 

What is the 3-digit number for the later model LS6 heads? And are mine the same heads just with a different number since they were made in mexico?

 

the most common casting number is 243. as far as I know they are the same the springs are a little different but that is because GM upgraded the springs in 2003. as far as just the heads go they are the same, I have only had one set of the 799's pass through my hands, sent to me by a customer.

 

I thought GM changed the springs in the '02 Models??