Converting Johnson 60hp to 70hp

[headdamage]

I've been looking at the parts books and as far as I can see the only difference between a 1996 Johnson 60hp and a 70hp is the orifices/jets in the carbs. Earlier 60's like my 1993 have different carbs but the 1996, the I've just picked up, seem to share them with the 70's.

Can anyone confirm this and have you converted an OMC 60 to 70?

Thanks.