timing???

[payaso13]

Hey guys...I have a stock 78 and installed pamco....works great but had some garggling sounds when slowing down to stop....so 5twins informed me I might not have done a proper timing at full advance which he was right I didn't....so with the help of a friend and timing light ready to go when I give it throttle as slowly as possible I get it to around 2500 Rpms and its like turbo boost kicks in and ROMs jump past 3000 or so....no problems when riding bike just trying to time it better and don't know why it jumps????