working on a 78 SB 400. Rebuilt the motor and went to install the exhuast manifold and the bolt holes did not line up. I have not ever had this happen. So I drilled the manifold holes to make some more room. still would not line up bolt holes. So heated up the manifolds (red hot) and forced the holes to line up. I am wondering if the manifolds will crack down to road from this bizare installation process