Hi Max,
I'm not sure if the Victa decomp is going to be big enough to relieve enough pressure in the OHV motor, it is a lot harder to turn over when it comes up against compression. I might have to try an Enfield decompressor on that one, get a copper pipe out of the head and then fit the decomp wherever I can. Wish I had kept the OHV head off the last motor I scrapped so I could have played with that one