Upsizing the Masterpiece Optimus Prime head.

I've got a Masterpiece Optimus Prime (One of the best toys ever made) and I'd like to upsize his head to 1:18th scale. How tall should the head be?? 3"? 4"? (I think the head could make for a great Dio prop).
Thanks!

Maybe 4 inch, it would look good with SE in fornt of him, like he just chopped it's head off.

Good call, J. This looks about 4"-5".

The main ball of his head (not including the 'uprights') should be about the size of the BUGG bathysphere, I'm thinking. How tall is that? It should definately be big enough to rig some lighting into and have a removeable panel or two to expose circuitry.

While looking for a pic of Mindbender rummaging around in Prime's head from the first Joe/TF comic; I found this pic, which has me intrigued:

Thanks, Jimbo. I now just have to find my Masterpiece Prime.
That human Prime looks great too. MAybe some shrinking is in order too.

Thanks, Jimbo. I now just have to find my Masterpiece Prime.
That human Prime looks great too. MAybe some shrinking is in order too.

You shrink that head and I'll kiss you square on the mouth. That means I want one shrunk please

And if you can't find your Masterpiece Prime let me know. I have the Hasbro version I can send you.

Ahhh, Chris, promises promises. LOL

I actually just found the Prime head, and made a casting of it. I'll upsize it tomorrow. And downsize it on Sunday.
I also just got a great Indiana Jones head:12" scale. I'm going to shrink that as well.