What, the piping?
You'd ideally want the same piping that connects the viper to a 172 TB - if you can get that you're sorted but if not get up to your scrappy as get something that looks similar. As for reduction rings, something thats in between the viper diameter and the 8v would be great - again, scrappy or some kindof hard wearing foam will sort you. You'll be clamping it down with a jubilee clip onto the 8v TB so it doesn't need to exactly fill the gaps...just enough so it fits well.