Vintage Ultima Front Wheels?

[Mushman]

Hello - I have just aquired an old Ultima pro, with a mind to racing at York in the Vintage class . The Only thing is that it came with old tamiya Astute wheels on and i would like to bung some more modern larger wheels on. I figure the rears will be no problem but the fronts im not so sure about they take a pretty big bearing with a - 10mm OD / 5mm ID.
Any info would be greatly appreciated