[Hogg]

Lets just say that GM isnt really into making a bunch of different parts that arent needed. The similarities are striking. There is some small differences in camshafts.

LSA t-body points forward to the drivers side at about 35º
LS3 points straight forward
LS9 is mounted offset towards the drivers side, and is slightly angled towards the passenger side and upwards.

Intake manifolds are different due to the following differences.
LSA single element intercooler
LS3 no intercooler
LS9 dual element intercooler



GM has built a naturally aspirated LSA, they just havent released it to the public, YET. It will be seen in the upcomming Camaro, RPO L99.

peace
Hog