For my money the tried and proven Avons or the new kid on the block Contis, don?t be put off by the price, they are cheap compared to a crash or frustration, and I am sure you?ll get someone to freight to you. Is there a racing forum in your country?
What size rim are you fitting to? Unless you use a tyre the correct recommended size for your rim, err in the direction of a wider tyre on a thinner rim, it is no good going with too wide a rim for the tyre.
And even with your hot big bore motor, you won?t have the type of power to need or use a big tyre like a 140. Have a look at the pics of the worlds fastest SF racer of SteveB (Breganzane), you can easily see the rear wheel in the pics on his website.