Intake Fitment
Most machine shops have a tool to check what the angle of the intake should be cut at. You will need to get the intake fitted before you go any farther. This probably was not done before installing the intake.
Take starting fluid and give small squirts around the parting line at the intake and head. also around the base of the carb. If the engine raises in RPM's this will locate a vacuum leak if any. The better way is a smoke machine tester . If you cannot drive the car to a shop with one use the starting fluid. Be careful not to spray to much at once if there is any spark you will start a fire.