All of the LS type blocks
have the same external dimensions.
Thats the iron blocks (4.8l, 5.3l and 6l)
And the aluminium blocks (5.7, 6.0, 6.2l and the LS7 7l block)
However depending on the application GM attaches different components that themselves have different dimensions, 2 good examples oil pans and intakes.
If you look at the truck style and car style (LS1, LS6 etc) intakes are interchangeable as far as attaching them to the cylinder heads, but truck intake is much taller than the car style.
The same type of thing applies to the oil pans, pretty much every oil pan will attach to any LS block, but the different oil pans all have different sizes, have a look at this http://ls1tech|http://www.ls1tech.co...-oil-pans.html
thread if you look closely you should they all have similar dimensions with the exception of how deep the pan goes - the truck pans are normally much deeper.