Ls transplant

Hi...I have a gq with a 400 chev, thirsty machine, great fun, but I'm looking at a LS implant.
Just to clarify do the LS engines still have the same bolt pattern as the cast iron chevs?
I think they may as this will make things a lot easier.
I bought this ute with vic registration and roadworthy, the 400's engine numbers are on the rego...but no engineers report.
So I did some research before I bought it, asking a number of automotive engineers where do I stand.
They said don't worry about it, it's already registered with a chev V8.
I don't know what sort of adapter/bellhousing was used.
I would love to hear from some of you, with their experiences with the ls engines, especially performance wise.
Do they have good low down lugging power, or do you have to shift down to keep it pulling? ...I hope to be able to chase up a 6.2 litre with a 6speed auto.