I'm using an f body pan on an LS2 with the DSE sub-frame for a second gen. with no problems. I used DSE's mounts also, there is very little clearance at the crossmember ( around 1/4 inch) but it clears fine. I also had an LS7 pan on the block while I'm still mocking up and it also clears. If your going to do many track days with the f body pan also look into the pan baffle from
www.improvedracing.com to prevent oil starvation during extended high G manuvers.
Tommy