Unless it is one of the pumper SF engines or one of the Hanno varients, it will run just fine. (also double check the info on the SF engine ..... the pumped ABC pattern engines were a little different than the ringed SF sport engines)
With a jett-stream you would want to prop the engine for between 12,000 and 13,000 rpm. 12x6 would be right in the sweet spot
Dimensions for the turbo-jett mufflers are on the website, along with a few example photos.
http://www.jettengineering.com/accy/turbo.html
Your application/installation would be most like the Corsair shown there. If you can compair your T-28 cowl to that of the .60 size corsair... that will be a useful reference.
The turbo-jett, by its nature, works in a lower rpm band. The 10cc muffler and the 15cc muffler work well from 10,000 rpm up to around 13,000 rpm - broader range to work with. You will not see as much of an rpm gain with the turbo-jett, but what you will see is that it will turn a bit more prop at that same peak rpm. For example, jump from a 12x6 on a stock muffler to a 12x7 or 12x8 with the turbo, and hold the same 12,000 rpm.
Looking at the BH T-28 manual on the hobby people website....... it is hard to tell if the turbo-jett would fit 100% - but it looks close.
For the jett-stream, they at least got your started with a muffler channel. Probably would not require much work to make the channel a little bit longer.