jjbiggers2

iTrader: (5)

I know its not recomended but who has done this? I have heard it can be done. I have a ls1 block that needs bored and a set of stock ls2 pistons.

ls1 1990 VN

LS1 Alloy block can't be bored...honed from standed 3.903 piston to 3.905/3.908

jjbiggers2

iTrader: (5)

I know that's what they say but I have read about people that have did it.

NVR_SPDS

iTrader: (39)

I believe the stock bore is 3.898, and can only be cleaned up to the 3.903/5/8 aftermarket pistons.

The walls just arent thick enough to safely support the bigger piston. Your pretty much rolling the dice on if it will last.

blk~2000~Z28

possibly after resleeving their blocks, which at that point it would make more sense to get a different block anyhow.

Canbarelygo

dont try to cut corners youll end up with a wheelbarrow filled with a thousand buttholes and a junk block. use your head.

ls1 1990 VN

mmmmm 'BUT' is this not what i said!!!

Cape T/A

Why would you not just buy some forged pistons while your inside the engine and then youll be able to take some abuse from power adders.

jjbiggers2

iTrader: (5)

The cylinders are to pitted from rust to make 3.908 bore size so that is why I was thinking of doing the ls2 pistons I have.

Isolde

iTrader: (4)

If you're gonna bore it, try for 3.936". If it cleans up there, you can get it honed to 3.94", order rings for a 0.030" overbored Mopar Magnum 5.2L, then order custom forged pistons to match, and have more safety margin than trying for 4.00".
But it might be cheaper to just buy a used LQ4.

kinglt-1

iTrader: (26)

This guy did it...

https://ls1tech.com/forums/dynamomet...s-xr281hr.html

jjbiggers2

iTrader: (5)

I knew I saw someone that has done it.

BlueBird346

iTrader: (13)

Read the replies in that thread. Its not a good idea.

SilverSS

iTrader: (30)

a 4.000" bore will leave your sleeve wall thickness at around .027" thick in an ls1 block. the grey iron sleeves are brittle and the aluminum supporting them is a joke.

89 formula350

iTrader: (8)

hard to say how long it will last. ive seen cylinder walls break open on gen 1 blocks. i think for the "chance" labor you had the machine shop put into this I would have tried sleeves for a fun chance. go big right off the bat


let us know how it goes. might just find the walls distort after time and poor sealing of the rings is all that happens