are you getting confused between the is engines ( lexus ) and the ls engine ( chevorlet ) ??
the ls engine came in 7 derivitives ls 1-7 , all different depending on cubic capicty , power output ect
there all alloy blocked motors , based on a smallblock chevvy lump ,
hugely tuneable ,compact and lightweight , absoultely stonking engines
had a look into one for my rwd mk3 esc project , but getting one seemed difficult to find at the right price ,
all up irrc they weigh about the same as a complete yb engine ,
what u thinking of putting it in ,
ohh and they are also found in vaux monaros
beef