is there a problem with 98/7 ls1s?

[Ishmael]

I read somewhere that the 98/7 ls1s were somehow weaker than 99 and on, is this true? Also, what's the safe limit on horsepower for a stock bottom end?
thanks
Scott

[Rhino]

The only major internal difference is that I believe the 98 and below bores had very thin sleeves and only allow for an extremely light hone.
In my opinion, the biggest negative about the pre 99 swaps (utilizing stock harnesses) will be a limited PCM with a different pin-out.

http://www.ls1tech.com/forums/1740880-post2.html

[daytonayellaz]

There are some block differences also, and some oiling issues.

[Rhino]

I did forget about the oiling issues, but weren't they due to the pump design?

[Ishmael]

I read something about piston slap but I can't remember why and I can't remember where I read it.

[wickdss]

Oiling issues to the cam, and the PCM is limited in what it can do. The oil pump issue was common till 2000. Bottom end is somewhat strong the weak link is the pistons. Rods are good and the crank is good for 800+hp.

Troy

[daytonayellaz]

Im pretty sure the block design contributed to the oiling issues as well. The piston slap problem was a issue all the way through at least 02. The pistons were so short that they could rock in the bores until the engine heated up enough and they expanded to fill the bore better. I had a 02 RamAir TA that only had 16k miles on it when I sold it.... it drove me nuts to listen to a brand new car that sounded like it had RODS knocking!! I was on the phone several times with GM over it!! The thin sleeves are a problem on up as well.... cant bore them at all. Its a throw away block in my opinion.....sorta like a disposabal camera You can have them resleeved, but why spend the money to put 8 sleeves in a 5.7 block?? was always my thought. Man.... how I remember doing all this research looking for the best/cheapest way to get a all aluminum motor for my swaps.