EDELBROCK PRO FLO 4

I just went through this process with a stroked 390, EQ heads and the Pro Flo 4. I used the 12pt bolts like you and dry fitted without the gaskets. During the dry fit I had to clearance 2 of the manifold holes where the runner and flange do not allow the bolt to go vertical enough. After I got a good dry fit, I went to install with gaskets and ended up needing twice the normal RTV bead size on the China walls and cutting all 4 inside intake bolts down (different lengths) to work. Those 12pt. bolts don't allow and open end wrench, which would've made tightening them a lot easier.