Did a dry fit on the Edelbrock big port dual quad intake just a while ago on cast 690s. The 881 that I took off had the upper bolt holes or slots cut down at one time to fit low perf heads. I have Moon valve covers on the heads and left them in place when I pulled the 881 intake, the manifold cleared the valve covers. When I put the Edelbrock between the heads the upper bolt holes or slots would not clear the valve covers in this area. Has anyone had this problem? Also the oil splash pan was not fit tight against the mounting surface port area of the intake and I think under the right circumstance it could lock the intake to the heads if you pushed the sheet metal below the head port area. Does anyone see this? I never did get a chance to see if the bolt holes lined up! I got out of the garage before I started to have a bad day. : I'll tackle the intake again tomorrow.