Well i just purchased a set of Standard size type s pistons for my jdm 95 closed deck, and my block code on top of the water pump says BBBB, now will i have to send these pistons back and get oversized type s pistons?, or will i be ok with the standard size i ordered and jsut clean the block and drop em in?

 

B pistons are just bigger than A pistons, dunt know by how much though.
You'd also need rods that support the floating wrist pin of the type S pistons, I heard that you can get the OEM ones rebushed, but havent seen anyone actually done it..........so also aftermarket rods............. I think the H22A4 came with floating type wrsit pins so if thats your block than your ready to go.......

 

Check out the FAQ for "the official A and B Piston Guide" or something like that.

Most people dont reccomend rebushing stock rods, but they can be honed out a bit to allow for the correct press fit instead.