I don't think that's normal for an original piston in a VH but you don't have an original piston....
The issue will be if any part of the piston 'dome' hits the inside of the hemi in the cylinder head (or if the piston rings are almost out of the barrel at the top - or if you've got a ridge at the top of the bore and the rings now have to traverse it to reach the top of the stroke).
I don't think the compression ratio is anything to worry about.
(Dunno about a VF though.)
Hope that's of some use - I expect there will be some more informed comments along shortly!
'55 Huntmaster, '56 VH, ' 51 VH, '80 R100RT, '00 Sprint ST (but all those Ariel parts can only make one running bike...)