360 driveability problem

timing is at 12 deg.at idle range.if i remember correctly.the distributor points at 1 when on tdc.the cam is supposed to be a like a 340 cam? i am kinda baffled on the situation and was thinking about pulling the front cover and inspecting the timing marks on the gears.but would hate to go through all the work if it could be something simpler.thanks for any help.i did not install this engine,it was already in the car..