I never liked Legacy Skullgrin's monster head. To me it seemed too big and it was trying to both a Pretender and Bot at the same time.
Like wearing a work suit but still with a fancy dress party mask on.
This started from me misinterpreting someone's else's customisation but I think it worked well.
I used my soldering iron to melt out a socket in Skullgrin's torso, jammed a Titan Master port in there (I think from TM Brawl's vehicle) and repainted a Quake head.
Next time I'm at the hobby shop I'll look for a closer colour match.
It can still transform with the head attached although a panel won't sit flush.
Now he can join Submarauder and Bomb-Burst!
Skullgrin helpfully points out what happens if the Titan Master is left on
An earlier attempt
Apologies, looks like my picture crops didn't save