Installing the classic dash for 1967 dodge dart

have you offered it in there yet? i'd remove the gauges from the panel and offer it in to see if it sits nicely in place. then if you can see any dash frame through a gauge hole or any part of the frame obstructs the fitment mark it for cutting. refit the gauges and offer it up again, you may need to increase the hole sizes slightly but better to creep up on it than cut too much.
that's how i'd do it anyway.
neil.