IH M Farmall-propane powered, H Farmall (father-in-laws), Ford 1300 diesel
What brand tiller? I'm sure someone here will have the same kind and can help, but I'm thinking Tractor Supply. Some of the dealers here can probably hook you up when they know what you have.
Here's the pto shaft/slip clutch/shaft extension I use for my 48"-wide Yanmar RS-1200 rototill and my Kubota B7510HST.
The shaft is the shortest one I found at Tractor Suppy Co. (TSC). Around $80. I had to cut it to fit.
Bought the Weasler slip clutch from agpartz.com for $65. That website is no longer functioning. You can get slip clutches at TSC and at Agri-Supply.com.
I needed a $15 shaft extension on the rototiller gear box to position the slip clutch so it wouldn't rub on the tiller sheet metal. Bought it from Agri-Supply.
Also had to remove the short 26" long Kubota lower 3pt arms and replace them with the 35" arms from my MF-135 to make enough room for all these parts.