I will check the combustion chamber volume on the old heads , the new ones are 65cc I think,
I think I have to go with the whiplash cam, as I don't want to get involved in the block work at this time.
The whiplash cam in a smaller capacity engine may push the power higher up the revs , so maybe ok.
When I've done it all I want to get it on the dyno, and see what it makes.
Maybe a sweep stake