Main and big end bearings

[blaze_away]

Just considering future options.

Is it possible to check and if necessary replace main and big end bearings with the engine in place ?

4.6 cross bolted top hat liners Serpentine engne.

[Classic Chim]

Yes. Rich ( Sheel) did it with engine in situ but on a ramp.

[Boosted LS1]

Can you remove the sump in situ, if so yes. No 5 main bearing could be a pita though.