so im going to go look at what ive been told is a jdm R motor. the motor needs pistons, don't care for that was gonna change them out any ways... price is 700 for short block... now here is my question... the kid was originally selling it with a gsr head, which made me think it was jdm gsr motor but he swears its a r block. i know the rods and pistons will have p73, and the rods with have a R stamped on it.. is there a way to tell the block its self and crank is a real R?

besides internals is there a diff between gsr and r jdm blocks seeing they have the same stamp on it....

 

Why does it matter? A itr block is the same thing as a gsr block so dont waste your money on the ITR name look at my signature. and as far as I know no there isnt a noticable diff.