Peugeot 103 50cc high-comp head made by Polini. High comp head was run down the street, once, honest. It doesn't have a decomp valve, so I plugged it with a bolt. Threads are fine and you could probably get one from 1977 mopeds
$30 postage paid... no pictures unfortunately, I promise you it's in good shape, just has some carb cleaner stain from testing for leaks.... they'll burn off when you run it.
For the budget-conscious mopeder. Get this super bargain to re-capture that tork after porting your stock jug.