I want to work on customizing another character for the Transformers Dark of the Moon. I don't need Jolt, but I may need his body but with a different head, maybe a gundam head. I want to know these questions. 1) Are Gundam Heads same size as a deluxe Transformers figure size? 2) Are there any Gundam head on ball joints? 3) I'm thinking of a Gundam Head on Jolt's Body and naming him Prowl, What do you think?
Pretty much all Gundam heads are on balljoints. Whether they fit or not is another matter entirely. Gundam kits generally used standardized joint parts, so the ball and sockets are all the same size. Transformers, not so much. You might need to splice the joint entirely, but it's possible. Best match, size-wise, would probably be 1/144 Gundams, but it'd work best for base bodies that have medium-ish heads. Some characters have fairly large heads (say, Armada or Universe Hot Shot), where swapping a 1/144 Gundam head onto their shoulders would look rather silly, and you might need to look into a 1/100 scale head instead (but those could wind up being too big instead). Also, this thread probably belongs in Radicons Discussion, rather than Toyark.
Most gundam heads are ball joints. As to size, i can't help ya. I always forget how which of my Transformers are Deluxe.