did the soviets ever let boxers fight in the olympics? anybody know?

Yes they did.

Here's a small list of Soviet fighters from the Olympics.

http://en.wikipedia.org/wiki/Category:Olympic_boxers_of_the_Soviet_Union

werent aloowed to fight professionally though were they? back then?

No they werent allowed to turn professionals.

One of the reasons they where so successfully cause this allowed em to send much more experienced fighters to fight against their younger less experienced opponents from the western countries.

the other reasons of course is the sowjet amateur shool is really good tough the Cuban and East German seems to be better.

Agreed. The Cubans were top; then the East Germans and third came the Soviets.