2 people have said dont do it. So do you want advice or do you just want someone to tell you that it will be fine and you should do it?
Here is your answer, 2 seconds of searching would have found the answer for you:
RB20 - 2.0 L (1998 cc, bore: 78.0 mm, stroke: 69.7 mm)
RB24 - 2.4 L (2428 cc, bore: 86.0 mm, stroke: 69.7 mm)
RB25 - 2.5 L (2498 cc, bore: 86.0 mm, stroke: 71.7 mm)
RB26 - 2.6 L (2568 cc, bore: 86.0 mm, stroke: 73.7 mm)
RB30 - 3.0 L (2962 cc, bore: 86.0 mm, stroke: 85.0 mm)