Well, I went ahead and tried converting a Super Pac-Man to a Grobda and it somewhat works if you swap 4F 56xx with a 58xx but even with the i/o MB8840 swap, I am having some player control input issues. Mappy PCB (pin2) and Super Pac PCB (pin1) use different pins for clocking the 56,58,59xx customs. I manually changed to using pin2 and gnd'ing pin 1 on my super pac but that didn't change anything.
<<Edit>>I had too slow 2114 ram at 2D. replaced ram it it appears to work correctly.
Note: J2 pin 16 = p2b1 and 17 = p1b2 All other controls map to standard Super Pac-Man
Super Pac-Man CPU board chip locations:
1B (CPU 1 code - 8KB type 2764)
1C (CPU 1 code - 8KB type 2764)
1D (CPU 1 code - empty; Gorbda has a 8KB type 2764 ROM here)
1K (CPU 2 code - 4KB type 2732; Gobda has 8KB 2764 here)
Note: My Rev F super pac board did not have through holes here so you have pins 1,27,28 to +5v and pin 2 to A12 of sound cpu
3M (sound waveforms - 256 bytes type 82S129)
Super Pac-Man video board chip locations:
3C (character graphics - 4KB type 2732)
3F (sprite graphics - 8KB type 2764)
3E (sprite graphics - empty; Gobda has 2764 here)
4C (color palette - 32 bytes type 82S123)
4E (character color lookup table - 256 bytes type 82S129)
3L (sprite color lookup table - 256 bytes type 82S129)