I don't own either Animated Prime or Ultra Magnus but was considering doing a custom of "Optimus Magnus" by putting Prime's head on Magnus's body. Are the heads close enough in size or is Prime's too small? I know Prime comes from a smaller price point but seem to remember that his head was pretty big.

 

the voyager one should be big enough

 

There's a Leader Class sized Knockoff out there if you really wanna get size-accurate. But the mouthplate does not move, its molded in the down position. Nice figure though.

KO on left, Hasbro Voyager on right




The Leader Class guys




Optimus Prime Leader Class Animated - Animated at KOTOYS.COM

 

cybertron optimus prime's head also makes a good fit on animated ultra magnus

 

Physically, perhaps, but surely from a stylistic standpoint it'd clash no end..?