I'm looking to swap my crankshaft from my b18c block w/ ITR one. Is this is good idea or what other b series motors are good match? Or just stick with the one I have.

 

I know that the ITR crank is a little better than the GSR but its not going to make a dirty difference.. i would stick with what you have unless the crank is free and the labor to swap them out is free too..Use your money else where, thats my opinion..

 

if you are going to change the crank, why not the rods and pistions too

 

Do yourself a HUGE favor and do NOT change your crank. The ITR crank is unnoticeably better than the GS-R crank. Also, each Honda crank is made for its own block! Most people don' know this, but you're going to need an extremely good machine shop (to install crank, bearings, and triple check clearances) and some good luck for it to be done right.

Most swaps need a custom set of bearings. In other words, NOT worth the hassle or risk. You cannot just drop a crank from another block into yours. This is the same reason you cannot just simply use the caps from another block without re-machining everything.