Clearance with Dirty Dingo mounts for a 1979 k10?

[TheBlueBomber]

So I've been fumbling around with these things for a little bit now... basically since I started swapping it in I've had clearance issues with the oil pan hitting the crossmember...

It started out here with the mounts adjusted all the way forward.


And now I've got it dropped down a little more with the mounts adjusted back.







Now I haven't made any adjustments to the long bolts because I ran out of time but I feel like that won't be enough to correct this problem





Now I've spoken to DD and they said you have to notch the frame with these trucks? Yet I haven't seen a single write up on having to perform that notch... they also said on the website under that part number there is a description saying you need to make that notch. Yet there is nothing on the website.
.. here is the link http://dirtydingo.com/store/product_...1369%7B15%7D52

What am I missing here?