RsSean

iTrader: (27)

I was wondering if anyone has found the safe bore limit for the gen 3 iron block 5.3?

I know the ls1 is 3.905/3.908 but I haven't seen the 5.3 specs. Was wondering if it was possible to bore it out to 4.000 plus safely wanting to run a LS3 internals

SweetS10V8

iTrader: (4)

You can not bore it to 4.00". I have seen a lot of people bore it out to LS1 specs and use LS1 pistons, but I have never done it personally. Thats as far as "its said" you can go with the 5.3L block.

supersick99z

iTrader: (66)

Definitely can't do 4". If I was you I believe they make a 3.903 piston so you could bore to that and god forbid something happen you could go to the 3.905 or 3.908 next time

Sales2@Texas-speed

iTrader: (5)

Safe is the LS1 spec, as mentioned above, at 3.90x".

lemkerailroad

i have punched mine to 3.905 and still have almost .200 left all the way around in the holes

putting together a 395/6 so i am testing waters people say cant be done and im checking everything twice

but yes a 3.905 is no problem

RsSean

iTrader: (27)

Thanks for the replies I guess I will stick my old ls1 stuff in it and let it fly

SynergyV8

iTrader: (1)

I punch mine out to the exact 3.898 bore spec of the LS1 piston. I was at minimum wall thickness for cylinders 2 and 6, so be careful. Sonic test before boring blindly to piston size.