OK, so I ordered a Edelbrock Performer (2176) intake for my '67 273 along with a Holley 570 carb... took everything apart and started installing the new combo. The intake wont fit!! It's not the bolt angle/ pattern, it's a bulge on the bottom of the intake. I think its hitting the casting for the lifters. Also, there's about a 1/4- 1/2 inch gap around the manifold. Has anybody else encountered this problem? Anyone know how to fix it? (sorry if my technical vocabulary isn't right)....