you can use a tank with the petcock on either side just the fuel line routing is different. The frame mounts for the fuel tanks for the different series are different but depending on how creative you want to get with your welder you can make a newer one fit the older frame. The geometry seems to be the same. so, it should look OK when you're done. As an aside, remember the "F" used a single tap petcock instead of a dual drop that some of the "K"s used. So, there is a "T" fitting in the line originally on these bikes to split the fuel feed (1 & 2 carbs, to 3 & 4 carbs). Also, CMSNL dot com has all the parts lookups for these old bikes, use them to look at all the diagrams for ideas on rebuilds & part numbers. I haven't bought anything from them so, I can't advise there. I actually have the last microfiche for my 1976 "K" but, try find a reader today for that.