360 trouble. please help

Alot of what is inside the motor i am unsure about. Actually anything inside the motor i am unsure about. I didnt mean to say 340. Its a 360. Last night we disconnected the vac from from the dist and set initial time at 5degrees btdc. I looked up the stock timing for an auto trans in 74. Also found a vac leak on both sides of the intake manifold. I just did gaskets at the end of last summer so maybe my the intake is warped? I will be tearing that off today and checking and replacing. I wish i knew more about the engine but unfortunatly i dont. 727 trans with shift kit 391 rearend bone stock heads.