so a ITR oil pump with a LS waterpump would use the same belt?
and also it fits in a b18a block?
does it help any at regular rpm driving?.. maybe a higher idle oil volume or something
Yes, same LS belt with LS waterpump.
GSR/ITR/LS, GS, RS 96 or newer oil pump is all the same part number, so yes the pump will fit a B18a which is almost identical to the B18b.