how do you tell the difference between a JDM GSR Block and a JDM ITR block

cause they both say B18C

 

hmm, if there is the vin number on it somewhere, do a car fax and it might tell you..

and usdm itr's say b18c5 huh?

 

these are the jdm blocks not the us blocks

 

take a look at the pistons!

 

crank pulley, and the alt belts.
jdm gsr alt part# xxxx-p72-xxx
jdm r alt. belt part# xxxx-p73-xxx
wil only work for jdm motors. usdm r and usdm gsr both have the same crank pulley and alt. belt.

btw the difference is that jdm R has a smaller alt pulley, so the belts need to be shorter. ofcourse they could switch the pulley on you, but just look at the pulley bolts to se if they have been off before.

 

there are no markings on the block or anything like that

one more thing which head is a pr3-3 is that JDM ITR?

 

yes it could either be a b16 head or itr

since that is the code for both of them usually