Does anyone know if there is a company that makes exhaust for a 20hp Honda? If so what a the brand and how do I get it. Also is here anything that I can do to get more speed? Would changing the prop help or maybe beefing up the carb. Any help or advice would be much appreciated.

We ended up making an exhaust for a GX670, It wasnt anything pretty but got the job done... because longtails are a 1:1 ratio you can improve the speed by adding performance parts to the engine (carb, air intake, ect.) However the speed will come after changing the pitch of the props... So if you can find performance parts for your engine, theorectically you could bump up in prop pitch to displace more water/mud... However your gains to cost ratio would way off and for the money you prolly could just buy a larger setup...

Who makes parts for the engine though?

http://www.ereplacementparts.com/honda- ... 53333.html

Here's a link to the stock replacement exhaust, but I am unsure it will fit on the go devil, as far as performance parts I haven't looked that far into it... like I said the price prolly won't amount to anything significant in speed gains that you would get from buying a larger setup...