RE: Telemaster engine??
Out of the MDS engines I have used the .68 is the best of the bunch. They are however Russia's revenge on the world, very poor castings and crap for metallurgy. The big trick to the MDS though {learned too late to save them} is the fact that they don't like Nitro. Use either FAI or no more then 5%. They didn't get the nick name Many Dead Sticks for nothing but it turned out to be misinformation about the nitro. Once I went to FAI they worked OK.
I have a lot of MDS stories, I went through three of the .58s. The .68 worked but did go dead stick often enough. 5% nitro fuel seemed to cure that problem. When they ran they were a true power house. Two of the .58s I had the case itself broke!! Pot iron?? Maybe. Horizon only sold them for a year or so. I just got rid of the few I had under the bench and the fellow was thrilled with them. He ran FAI fuel and they were designed for it.