too much advance timing

i cant get my car to time right. i set the initial timing at 10 advance. then when i reconect the vaccum line it jumps right to 45 total timing. what could be the cause of this, and how can i fix it?
i know i should be running about 36 advance.
any help would be nice. thanks

Sounds like you may have the vacuum line attached to manifold vacuum (below the throttle plates) instead of ported vacuum (above the throttle plates).

Read this article:

http://www.chevyhiperformance.com/howto/97438/