Modifying 1979 c10 motor mount perches to 66 c20 frame

[russellrox]

I am having issues with motor mount perches. I have a 66 c20, with a swapped in 79 c10 crossmember to convert it to a c10. My issue is the 79 perches sit about 7/8 of an inch too high. What do most people do to modify these to work? I am thinking of going with the spacer route but I would have to trim some frame to make them bolt up properly. Pics if possible on what is needed to modify. I have dirty dingo sliders for my LS swap already so I am set on using this style.