My son and I are restoring a 81 280zx 2+2 and just found out the exhaust manifold is warped. The manifold is a F54 which is very hard to find. I can find a manifold that goes on a 1980 and has a different number. All the ports are the same, the only difference I can see is one heat shield screw hole is not molded into the manifold. Can I use this manifold? Thanks for the help