I use a GVP SCSI card without RAM expansion, this works well with a A2630. Try to de-populate the RAM on your GVP - I strongly suspect a clash of ZorroII address space. *If* the GVP is visible with no RAM, then try to populate it again in 2 MB steps. AutoConfig normally deactivates all Zorro cards it can't fit in the ZorroII adress space.
BTW1: It might be that the simple calculation "2MB 2630 + 6MB GVP = 8MB" won't work, you often have to to this kind of magic in 4MB steps (i.e. only 4MB on the GVP).
BTW2: You do not switch between "68000" and "68030" but you switch the whole accelerator board on/off (incl. RAM!).
