I bought a set of Dougs manifolds and used a Remflex gasket
When using non-original manifolds, the screws must be 1 1/4 be to fit properly. With the Stage 8 header mounting bolts, you don't have to worry about them being reversed. Run the engine for 15 minutes, then retighten and secure the bolts.
Pros
The double hex head includes a countersunk 3/16" hex head for easy installation