I have a 406" and had an airgap on it. I switched to an M1 and I love it. It actually picked up the 60' and gave me another 600 rpm of power. I only have the MP crate motor cam with .501/.513 lift (hyd roller) so I was shocked the intake made this much differance. It was also good for .45 on the ET. Give it a try.

76' Volare, 5.9 magnum w/Iron heads. New best 10.68 at 123 mph 1/4 mile.