can someone tell me what kind of exhaust manifolds i have.??
 

I just bought a 76 trans am 455 4 speed about a month ago,and the exhaust manifold look like ram air ,but i dont know what they came off or what year they are, here is the the casting # 478140-1 any ideas.? and why is there only 3 bolts that hold each manifold on.?

okay,book says 478140 is 1970 RAIII left side GTO/FIREBIRD manifold.

now the 478141 1970 RAIV-HO455 left side GTO/FIREBIRD manifold.