Thanks a lot psullivan for replying me my question. Well, other people did give me good information and knowledge as well. One point of you is right that why would I spend a lot on 4 stroke engine, well, the country I live in, which is Pakistan, here we have a lots of scrap come to use them in many metals, so in scrap we find a lot of engines come from many countries in the world, which are almost new, I would look for a 4 stroke engine for my 60 size otherwise, I already have HB .61 engine for that plane You guys won't believe how much I bought 2 engines, they are as good as new, in my country's currency they cost me Rupees. 600, which equivalent to US nearly $11[X(] would you believe that? Well, in future Im planning to move to Texas, USA, cos my wife belongs to Texas. The engines which come in scrap imported from all over the world its your luck to find good one, most of them are new but have dust, sand and other crappy stuff in it. One lucky guy got a JetCat turbine in that dont know what size is it, but I heard he got it for nearly US $200 to 250 Bucks, a real surprise but only luck counts and we have to spend their hours in order to find those engines. Anyway
once again thank you all very much for your replies, and support.

Have a great safe flying!!!

Mody