1976 360 engine swap

Hey all- Continuing the saga of fitting a 360 into my original poly 318 dumptruck....... I got a 318 flywheel, and modified it per the drawings someone emailed me...... but it was a 130 tooth, and my bell is for a 143 tooth......so needless to say, the starter didn't mesh. Got another 318 flywheel, nice shape- it's the larger 143 tooth. Starter meshes fine. I modified it to 360 specs re: the drawings...... Got it installed today, and fired up the engine for the first time. There is a vibration. Can anyone tell me why ???? Any ideas what to do to rectify the problem ???? I followed the plans to a tee- 3 holes to the right depth, exactly to the specs of the layout..... I don't get it.

10.5/11........130/143.......internal/external
Dang mopars anyway !!!!!

Ryan