Here's the best I can do. It's a little tight in places, and it seems there's always a hose or a wire loom in the way. Lot's of pics, hopefully this helps someone...
Distance from front of stock LQ9 timing chain cover to rear edge of front subframe crossmember (roughly 6 5/8"):
Distance from flat bottom surface rear crossmember of front subframe (confused?) to the machined engine block surface where oil pan bolts up (roughly 6"):
This is where I took the above measurement from:
Distance from firewall to rear edge of driver's side cylinder head (2 1/16"):
Top view looking down, distance from firewall to rear edge of valley cover plate on passenger side (3 5/16"):
Distance from front flat surface of Holley LS Retrofit Oil Pan 302-1 to rear edge of front subframe crossmember (6 3/4"):
This is where I took the above measurement from:
