Didn't see much info on here about this besides "same stud pattern!!", so I'm putting it in writing for the people. Did it for derbi but could be useful for Puch or anything similar.
I've been getting my derbi pp back together after dumb frame issues, and got super curious about 43mm stroker Minarelli vertical kits. There's 2 versions of these kits, 80mm and 85mm conrods.
I got the Athena 43mm stroke, 85mm rod.
So in my head i was like ok i have a 43mm stroke and 90mm conrod, I'll get the 85mm kit and make a spacer and live a happy life. Wrong. Turns out the deck height on the Minarelli cases is much lower, so my kit was about 1.5mm too high. Usually, I'd give up on the kit at this point but i had some very nice people (thanks Dave 🙃 ) help me machine the base of the cylinder 1.5mm, getting the port timings and squish right where i wanted them.
Anyway, the stud spacing is a little bigger than Puch, a lil smaller than derbi. Drill the stud holes out like 2mm in diameter bigger and you'll fit on either one. Case matching is a breeze on derbi, so much material on the front. I alumiwelded the back as a precaution, and I'm glad i did because I blew threw a bunch at the top. On puch, you won't be able to run it without adding material to the front, and to the back if you're going for the deep match.
Here's the cases close to matched.
I've seen people like jbot run an AC head with scooter kits just fine, but it didn't get me around the block with comfortable temps even with the biggest head i had laying around. I ended up using a treats LC/AC head with awesome temps. Rode around, ripped up some SF hills WOT and barely passed 180°. Bike is fast, life is happy.
shout out Polini x1 radiators on eBay which are going for cheap and are a good alternative to those bulky dirt bike radiators.
Glamour shot + quick rundown
-Athena 47.6mm Minarelli Vertical Stroker
-treats Athena lc/ac head
-Voca Derbi V-Protos exhaust
-HPI mini rotor
-Hobbit Xtreme bell
Mmm that's it