There are no real conversions on this model - the body is from the Ork Boyz sprue and the head is from the warbiker set. He does have a plasticard wrench hanging from his belt, but it's not visible in this shot.
This is the first Grokkenstern model:
I didn't realize that the head had the metal plate bolted to it when I built him, but he did manage to get a head wound in his first game, so it was appropriate (though the Doc sawed his legs off and replaced them instead of trying to correct the head wound, so I ended up making another version of him with De-lux Kickin' Legs).
Finally, here is my first biker, Squiggenkrantz:
In our rules, 'Elmets work in almost the same way they do in Mordheim (1 toof, 5+ save to downgrade what is basically a "stunned" result to "knocked-down"), and I usually give them to my bikers first - but it made sense to have at least one bare-headed biker for starting mobz. I probably ought to magnetize his head so he can be both, but I'm a bit lazy.
That's all for today, Squiglets! Until next time...