qestion abous s40 t4 engine......i would like to buy an s 40 engine or an s40 t4.i would like to ask ho knows about the engine if it can be havili modified withou chanching the piston and other internal pieses....please answer thank you so much ....i hawe a 440 turbo modified that is wy i ask ...!

 

I have seen some American models take about ~350, maybe 380(Crank hp) before the internalswere modded.
Just to be safe...I would do internals on anything above 350.