Diagram for intake manifold on Chevy 350?

I have a 1986 chevy 350 V8 w/newer style Edelbrock alum heads. I started installing a Edelbrock Pro-Flo Fuel Injection system and can't get the two center bolts started due to the center theaded holes on the heads being at different angles. What is the angle between the two holes and can I remachine and spot face new holes. Please help Ken