hard to tell from the photo but if that is the furthest forward point on the intake manifold there should be a bolt there (if i recall correctly). The bolt head (captured washer?) should hold the intake manifold tight on the right and the exhaust manifold on the left tight to the block. not only would this potentially result in a whistle from the intake but judging by the exhaust gas marks on the gasket by the exhaust manifold youve probably got a substantial ticking as well yes?