is there a difference?

 

yes the LS has a longer stroke
i belive the GS-R is 87 mm stroke and the LS is a 89mm stroke

 

can you use a ls crank in a gsr block without needing custom pistons, I want to built a motor with the gsr block and b16 head (poor man's type r). I was wondering which crank and rods to use, I will be using ctr pistons.

 

Gsr crank has narrow rod journals and you need to use the gsr rods with it.Gsr blocks and ls blocks are the same hieght.Ls rods and crank will work in a gsr block with ctr pistons.
Glenn

 

Thanks