603 tyres

[will7262]

Looks like I am getting a set of Blenheim alloys for my 603.
I have as far as I can tell a choise of either 215/70 or 225/65 tyres.
Given I am looking at a stroker 408 ci. engine for more torque can anyone shed any light on the pros and cones of these tyre options? I assume the 70 section will give a better ride but the 65 ratio will give better grip.

Obviously the rolling radius for thse twio options may impact on my speedometer
so again any feedback on this issue will be appreciated.

Cheers
Will