yes im weighing out my options . after three motors . i have one good block (rotary surface). and two cranks . a two carb set up, a single carb set up, ,good heads . 2 cylinders and pistons now are the issue which to use . i have to complete my disassembly of the sbt motor to see condion of the good sleeve one has low compression , .. being its from sbt i bet its over size ? . i like the original brp pistons they look as there quality is a little better the the oversize set. i trying to do this build without buying anything more. i have the money, but this is just my thing . tinker and use what i have . i prefer to cut out any dealership and or machine shop i dont want to even buy a new top end i should have two good out of 6 lol ., should.... piston rings i will buy ! how much is a set for both pistons would you think roughly. ? if i use the original brp pistons. vs oversize is there a price difference between these type piston rings and quality . i may have no choice but it may alter my decision . if the overbore is the next size what would the cc's be ? any hp gain from larger bore i would think a little. should the jets have been changed for more fuel. the oversize has 175 main jet single carb ,i guess after running motor and reading the piston for the sure answer but usually there a recommendation to start with . a lot of questions i know .... you know a lot more then i do , i do know do it right the first time .. im being cheap but as long as i build smart it will be good !!! has anyone ever run a different size bore in each cylinder and have a good running motor ??? thanks for suggestions , i figure id throw this stuff out there in my post i dont want to bother anyone to answer all this i can figure it out but it will take a lot of time reading the posts , ill get around to it but i figure this may help others also whom like to build on a budget . thanks again