ive heard that the 98 ls1 block is different then the 99 and up. does anyone know if that is true?

 

Yes that is true. The 99 and up blocks have a better oiling system which makes them more desireable if your going to hot rod it.

 

Try the search function. It seems like this question gets asked every three months or so.

 

thanks i did a search and it heled alot. it seems the 98s have thinner sleeves but are still pretty strong, i was planning on putting 6.0 heads on it since i am boosted and it looks like i would need new valve covers since the 6.0 are center bolt, but then it looks like the water jackets on the 98 are in different spots then a 6.0? is that correct?and what head gaskets should i use? thanks!