The LS1 is a whole different animal. The LT1 is pretty much a run of the mill 350 with fuel infection (iron block, iron heads, standard head port shapes, 4" bore) The LS1 is an ALL aluminium motor (alum. heads, alum. block) The runners in the heads are reshaped completely and flow VERY well stock (you wont ses an aftermarket head for a LS1 because of it) ~3.9" bore, 6 bolt mains, coil on plug design so no distrubitor (LT1 has the optispark~ pretty much a distrubitor).

Theres a lot to seperate these 2 machines, but dont underestimate the LT1s, can can be drivin well.